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Clean Up Your Windows Registry

PC Notes
By Martin Walker

Iomatic's Registry Medic can automatically scan for and repair a large variety of Registry problems. Most importantly, it backs up anything you might have changed, just in case you ever subsequently run into problems. You can see in this screenshot that over 300 errors have been found and 45 missing files traced to other locations.Iomatic's Registry Medic can automatically scan for and repair a large variety of Registry problems. Most importantly, it backs up anything you might have changed, just in case you ever subsequently run into problems. You can see in this screenshot that over 300 errors have been found and 45 missing files traced to other locations.

Even if you've cleaned out all references to old hardware from your Windows registry, it's a fair bet that it's not quite as spick and span as it could be. Housekeeping tasks and installations leave behind their own trail of junk, but fortunately it can be removed. Find out how...

The Windows Registry is a vast repository of references to both hardware and software installed in your PC, and its correct operation is vital to the smooth running of your machine. Windows constantly refers to it for information about each user and their preferences, the types of file each application can create, what hardware is available, and which ports are being used. In SOS June 2004 I explained how to spring-clean your Windows Registry to clear out references to hardware that no longer exists, so let's complete the subject this month by turning to software.

When you first install any version of Windows onto a freshly-formatted partition, the Registry contents are clean and relatively compact, but once you start installing your applications the Registry grows in leaps and bounds. Unfortunately, removing an unwanted application using the standard 'Add or Remove Programs' applet is rarely thorough, and usually leaves some detritus in the Registry. The dedicated uninstall options provided by many applications (usually with a handy shortcut somewhere in the Start menu) are normally rather better at cleaning up after themselves, although even these have a habit of leaving a few invalid references behind.

Your registry may also contain lots of useless data caused by simple housekeeping — if, for instance, you change the name of a folder or move it elsewhere, references to the original path-name may linger in the registry. In addition, uninstalling DirectX plug-ins may leave long lists of preset information behind.

This unwanted data clutters up the Registry and does absolutely nothing useful, could marginally slow down your PC, and may sometimes even cause it to crash, especially if it contains references to non-existent files. Windows 95, 98 and ME used to suffer quite badly from such registry 'bloat', but fortunately it doesn't seem to be such an issue with Windows 2000 and XP. Nevertheless, the SOS forums regularly have posts from PC musicians who want to give their registry a good clear-out, so I've been keeping my eyes open for a utility I can recommend.

Tiny Tips

It's surprising how many people ask this question on the SOS forums, but since they do here's a timely reminder. If you've just bought an item of PC or music gear secondhand and need a manual for it, the best place to start looking is on the manufacturer's web site. If, on the other hand, you need a spare part, more information, or just some advice, the manufacturer is once again the best place to start. You can do this via email (most companies provide contact details on their web sites), but for the larger companies a phone call is generally the quickest route. And the easiest place to find the phone number? Just turn to the back of SOS and read it off the alphabetical Advertisers Index.

Repair & Restore

Over the years I've tried a lot of utilities, ranging from freeware to full commercial programs, that claim to clean and repair the Windows Registry automatically, deleting references to long-gone software. Microsoft's own freeware RegClean is useful, if not particularly thorough, only fixing problems in a few Registry areas. Although it's no longer supported by Microsoft themselves, version 4.1a supports Windows XP and 2000 in addition to the Win 9x family (I found it at

I've found most of the remainder of the utilities I've tried either too fiddly to be worth the bother, or too enthusiastic — as anyone who has ever deleted even one registry entry that they shouldn't have will already know, the results can be catastrophic, sometimes even preventing Windows from booting up next time. For this reason, it's far better to err on the side of caution and leave your registry well alone, unless you really know what you're doing. Even then, take a backup of it before making any changes, just in case.

Windows 9x/ME makes a backup of the registry each time it boots up, and maintains up to five versions for you to restore if you ever run into problems (use the Ctrl key during bootup, select 'Command Prompt Only', and then at the DOS prompt type 'scanreg /restore', without the quotes, and press Enter). Unfortunately, this isn't the case with Windows NT, 2000 or XP, and if you use the 'Export Registry' function of Microsoft's RegEdit utility the resulting file can't be used to replace the existing registry, only to merge its data with the current one — which is of no use when the current one is corrupted.

The simplest way round this limitation is to use Lars Hederer's freeware ERUNT (Emergency Recovery Utility NT ), which runs on Windows NT, 2000 and XP, and lets you back up and restore their Registry data. If you download it at you'll also find his NTREGOPT utility in the bundle. This optimises the registry files by removing slack space left by modified or deleted entries, and can compact them significantly without changing any of the data within. As always, you use such programs at your own risk, but I've found them to be useful and reliable, and anyone who indulges in manual registry 'tweaks' would be well advised to use ERUNT first, just in case.

Registry Medic

Fortunately, after discarding a variety of registry-cleaning utilities for one reason or another, I've finally found one that seems to fit the bill nicely. Registry Medic (shown above), from Iomatic (, is a shareware utility that scans the registry to find invalid references, repairs those where a file or folder has been simply moved, removes others where the file or software has been deleted, including invalid Start menu entries, and kills Trojan viruses that use the registry. It runs on Windows 95, 98, ME, NT, 2000 and XP, so it's a one-stop solution for any type of Windows installation you have on your PC.

To give you an idea of the thoroughness of this utility, a quick trawl with it through the registry belonging to my XP Review partition discovered 297 invalid entries referring to long-gone files and folders, 51 start-menu entries that had been either moved or deleted, seven empty folders relating to software that had been uninstalled, three entries containing invalid uninstall information, 15 relating to shared DLLs that didn't exist, 25 to non-existing ActiveX, OLE, or COM entries (mostly, again, left after uninstalling software), five invalid Windows fonts references left after uninstalling Reaktor, and 23 invalid MRU (most recently used) and History lists.

One thing Registry Medic won't do is deal with registry references to old plug-in preset data, since even if the plug-in's files have been deleted the preset data is still valid, but you can enter the plug-in's name into RegEdit 's 'find' function, if you wish, to track these down and delete them manually.

Since some Registry cleaners, as I mentioned earlier, have a nasty habit of being too enthusiastic and deleting entries whose absence cause problems later on, I spent a long time after my first Registry Medic scan examining the results more closely. You can do this by selecting a particular invalid registry entry and clicking on the 'Open Registry key using Regedit' icon, to launch Regedit with the offending item highlighted.

When you're happy with the scan results, and have either accepted them all or decided whether to manually exclude certain classes or individual items of data (using the 'Delete Entry' or 'Keep Entry and Do nothing' options), you just click on the 'Repair/Delete Registry' icon to finish. You can also exclude references to specific drives, files and folders, to avoid (for example) references to CD-ROMs being flagged as errors, and define the search path when searching for file matches.

Since I couldn't find a single item that it wouldn't be safe to eradicate or re-link to an identically named file that Registry Medic had found elsewhere, I deleted the whole lot in one go. I then spent some time using the cleaned partition to see if any problems appeared, but none did. As it happens, Registry Medic automatically backs up any changes it makes, so you can restore them later if you do have problems. This data can be saved either as a single file per day, to which all deleted references are added, as a separate file every time you use it, or by the hour — or even by the minute! Where a file referred to by a specific registry entry does exist, you can also open its folder from Registry Medic in Windows Explorer, to check for yourself.

The demo version of Registry Medic will find all the faults in your registry, but will only repair/delete five items each time you scan, as an incentive to encourage you to register. However, registration only costs $19.95, and I was pleased to see that Iomatic provide registered users with minor upgrades at no extra charge, plus rapid technical support — they replied to my emails within one working day.

Overall, I was most impressed by the thorough way in which Registry Medic dealt with registry bloat, without causing any damage in the process, and how it automatically saves the changes it makes so that you can back-track in the unlikely event of any problems. It's far safer than attempting to delete entries by hand, even if you are an expert user.

Intel Dothan Processors

Dothan CPU.Dothan CPU.Intel's new Dothan CPU (top) uses a different manufacturing process to cram 80 percent more transistors and double the amount of L2 cache onto the die, compared with the Banias it supersedes (above).Intel's new Dothan CPU (top) uses a different manufacturing process to cram 80 percent more transistors and double the amount of L2 cache onto the die, compared with the Banias it supersedes (above).Over the last year or so there's been an enthusiastic take-up of Centrino laptops by musicians, largely due to the excellent processing power of Intel's Pentium M 'Banias' CPUs — plus the fact that such laptops are generally half the weight of equivalently powered 'desktop replacement' models, and much quieter — as well as having batteries that last around twice as long. However, on May 10th 2004, after being originally slated for release at the end of 2003, Intel finally released their successor to the Banias, codenamed Dothan.

Intel have had an uphill battle convincing high-street customers that a Centrino with 1.7GHz Pentium M processor is equivalent in performance to a much faster sounding 2.5GHz Pentium 4 desktop-replacement model. So Intel have abandoned clock-speed designation with the Dothan, instead (taking a leaf out of AMD's book) adopting a new naming scheme that focuses on overall performance, including cache size and buss speed.

There are initially three new Dothan processors — the Pentium M 735, 745, and 755 — running at clock speeds of 1.7, 1.8, and 2.0GHz respectively. Personally I think these new names will cause even more confusion, since they provide no indication of relative clock speeds. However, compared with the 130-nanometer manufacturing process and 1MB L2 cache of the Banias range, all three Dothans are manufactured using a smaller 90-nanometer process, which means that Intel can fit 80 percent more transistors into the same space, and incorporate a 2MB L2 cache. This new process also incorporates new technologies that enable faster clock speeds and lower power consumption.

In some benchmark tests the fastest (2.0GHz) Dothan has outperformed the fastest (1.7GHz) Banias by 22 percent, and while battery life won't be much longer, you'll be able to run significantly more plug-ins before you run out of juice. With no prospect of faster Banias models, a Dothan-capable model seems the only way to go if you want a new Centrino, although as I write this in the first days of June a 1.7GHz Dothan laptop seems to cost at least £200 more than a 1.7Ghz Banias one.

As usual, companies such as Dell, Gateway and HP were very quick off the mark with new Dothan-based models. A few Banias Centrino models can also have their BIOS updated to use Dothan processors, but most can't be updated, including Compal's CL50, favoured by many specialist music retailers. Compal have instead released a Dothan-based CL56 model with a new livery and 128MB ATI graphics module. First off the mark with a Dothan-equipped model among specialist music retailers is Philip Rees (, although most should have a Dothan laptop by the time you read this.

Published August 2004