Just wait until your computer slows down,..
and no defragmenting, virus- and malware scanning or any other intervention seems to help. FIRST: Read the Basic Advice Page!

So, clean up that registry and your machine will run as new?
...in theory! Besides all the crap in your registry, how many resident soft is active on your machine? Eating resources... Right! Install new software intelligently.

ALWAYS make a registry back-up or System Recovery Point before you clean up with these tools.

More info & help:
www.windows-help.net/WindowsXP/howto-18.html
windows.about.com/library/weekly/aa020120a.htm

2 obvious tools for daily use:

BeClean (5/5)
Cleans superficially the registry, internet traces, history, temp, broken links in start menu and on desktop, recycle bin, computer drives & custom files. Perfect for daily use! I trust it 100%. Allows you to automatically clean-up on boot. This is fairly “old” software and had no updates since a long time,... but still does a brilliant job.


Crap Cleaner (5/5)
Cleans registry, internet traces, history, temp, etcetera... allows you to keep cookies,... scans within Spybot S&D: I disabled that option, lets you uninstall a program and runs very fast. Allows you to automatically clean-up on boot. Unscore - during install - the option to co-install the Yahoo toolbar unless you really want that.


What to do if you want to perform an occasional deep cleaning?

In the old days I used - like many - old faithful Registry Cleaner. A fine piece of freeware! I still have version 4.3 running on one of my older pc’s and it still does a brilliant job. But it’s no longer available.

Download a 30 days (fully functional) trial version of it’s successor (set of 3 tools):
jv 16 PowerTools (4.5/5). (payware - fully functional trial) (EXPERTS)

You can also download from the same software developer the 30 days (fully functional) trial version of the stand-alone registry cleaner RegSupreme (4.5/5). It still looks and feels like the old Registry Cleaner. It does an even better job!

Be aware... always ask the software to make a back-up copy of your registry,... just in case! And use it at your own risk!

If you’re not at ease,... do get professional help! They’ll run the same software and ask you more than what it takes to purchase a fully functional version!

www.macecraft.com
PS: Nondisputandum did not subscribe to Macecrafts partner program.
No gain, no pain!

Spybot Search & Destroy 1.3-up (5/5) has included a monitoring tool that runs transparently and will warn you when an important key or entry in your registry is added or changed. It will blacklist potentially dangerous processes.
... more about Spybot (spyware tracker)

Erunt (4/5)
Auto registry backup & reinstall

StartupMonitor (4/5)
Runs transparently and notifies you when any program registers itself to run at system startup, prevents from registering themselves and acts as a security tool against trojans.

Registry Prot (4/5)
A standalone, compact, low-level realtime registry monitor. Will alert whenever a key is added or changed, and then give the option of accepting the key change, reverting back to the original key setting, or deleting the key. Acts as trojan detection.

BHODemon (5/5) but even better is using Mozilla Firefox
For Iternet Explorer addicts. BHOD allows Browser Helper Objects to install themselves without your permission. Some of them are extremely harmfull, even viral. Use BHODemon to check your registry and look at & manage the BHOs that are installed. (see also: anti-spyware page)

PC Inspector File Recovery (4/5)
Recovers deleted files. Works with FAT16 & FAT32 & NTFS systems.

1. Once, compared to the average user, you have some expertise, try to poke around in your Windows configuration & services. Poking around is +++ at your own risk, obviously. You can access these tools through your Run Box (start > run):

• msconfig
• services.msc

2. The Windows Taskmanager is accessible by doing 1x ctrl-alt-del. You can see your system performances, give more or less priority to a process, stop a process, check network activity, cpu-usage and more.


3. A more (non-Microsoft) powerfull tool to kill or cure activity is Sysinternals - Process Explorer. (5/5) If you dare to take the risk to kill an active DLL process, download Process Explorer. This tool from Marc Russinovich will come as a zipped file that needs to be unzipped in any place on your hd you like. It’s a stand-alone tool. In the options, you can set it up to replace Windows task manager. <the author> The Process Explorer display consists of two sub-windows.  The top window always shows a list of the currently active processes, including  the names of their owning accounts, whereas the information displayed in the bottom window depends on the mode that Process Explorer is in:  if it is in handle mode you will see the handles that the process selected in the top window has opened; if Process Explorer is in DLL mode  you will see the DLLs and memory-mapped files that the process has loaded. Process Explorer also has a powerful search capability that will  quickly show you which processes have particular handles opened or DLLs  loaded.
The unique capabilities of Process Explorer make it useful  for tracking down DLL-version problems or handle leaks, and provide insight  into the way Windows and applications work. </the author>

Before you do anything else,... run LSPFix:
www.cexx.org/LSPfix (5/5)
<Author> A free utility to repair a specific type of problem associated with certain  Internet software. This type of software is known as a Layered Service Provider or LSP, a piece of software that can be inserted into the Windows TCP/IP handler like a link in a chain. However, due to bugs in the LSP software or deletion of  the software, this chain can get broken, rendering the user unable to access the Internet.<Author>

WinsockFix (testing)
Another tool to repair your internet connection setting. (After cleaning) or after removing certain malwares.
(Credits: Max - alt.privacy.spyware)

RegClean (5/5)
This Registry Cleaner from TweakNow.com does a fine & secure job. It is very simple to use and it has some options to tune the cleaning. It is part of PowerPack (payware) but RegClean alone is free for non-commercial use. It is capable to mark what is unsafe to delete.

Glarysoft Registry Repair (testing)
Registry cleaner with restore function, not fast but profound scanning and cleaning. Detailed results. Also cleans Spywares and Adwares that abuse the registry. The free version does it on demand. Their payware version does it in the background and says to offer enhanced system fixing.

Unlocker (5/5)
If you get the message: “Cannot delete : Being used by another program.” or “Access denied”, “Sharing Violation”, “Write protect”... or a similar message. Download unlocker. It installs an extra right button tool to unlock the program or file. If ever you get locked,... a must have tool to overcome the obvious Windows bug.

Advanced WindowsCare (5/5)
This polyvalent tool from Iobit can (among other) repair and fix Windows and it’s registry within a few seconds. It got pro & con reviews during it’s beta testing but now it has a stable and solid final product. What you get for free is the light version of their payware tool. Light? Well,... adopt this welter weight ‘cos it does a good job. For the record: As a malware cleaner it sucks but you can pick another tool for that purpose.

FreeRegistryFix (/)
Smooth Install, nice & easy lay-out. It found on the double 474 registry problems among most in the TypeLib section, but also 44 activeX interfaces and 64 broken links. And that is right after CrapCleaner did it’s job. A good thing is that it has an undo button... but before that it frooze... hmm.. tried it again and it told me it repaired 50 problems for free and now asks me to buy their product. Well,.. i’m not hushly convinced. This is payware hidden in a free jacket. Nothing wrong with that, but not my cup of tea.

Drive Cleaner (stopped testing).
This looks smooth, but seems all to simple. The disk cleaner is the Windows Cleaner, it even has a spywarescanner that seems to to do nothing. Besides that is has a rather fair cleaning section and that’s what this tool is about. But as I’ve never heard of it before october 2005 i would not advice you to use it at the time. I’ll test it for a few months befor I give it a score - or dump it. Oh yes,... another thing. Their website is plain ugly.
STOPPED TESTING 12/2005: A-squared2 found a trojan in the downloadfile (exe). It was also found in the uninstaller of DClean. No other spywarescanner gave this result. False result or not? I stop testing and clean-up my system.

ECleaner (4.5/5)
Does a very good job. Detects also duplicate files and cleans up temp files. Available in many languages. Be aware what you remove!

Empty Temp Folders (4.5/5)
If you can spare a few minutes to set this tool up,.. you have a brilliant temp folder cleaner that does a better job than any other temp cleaner. A good alternative for those who know what they are doing.

Index.dat suite (4/5)
Allows you not only to delete the index.dat files, temporary internet files, temp files, cookies and history, but it also allows you to view the index.dat files on your system.
(Advanced users.)

RegSeeker (4/5)
Manage registry items. Search registry by keyword. Clean registry. (Advanced users.)

System Security Clean (4.5/5)
Internet tracks, junk files, cookies, index.dat, typed url, temp, custom folder. + Vieuw & stop startup progs.

DLL Archive (4.5/5)
Clean-up those long forgotten DLLs of deleted programs. You can delete or archive (& restore).

AM-Deadlink (4.5/5)
Detects dead links and duplicates in yout browser bookmarks. Supports Internet Explorer, Mozilla, Opera and Netscape.

Startup Control Pannel (ONLY EXPERTS)
Shows and allows you to clean the START-UP folder with the ability to edit or add entries.

PageDefrag (ONLY EXPERTS)
Has the ability for you to see how fragmented your paging files and Registry hives are, and to defragment them. It defragments event log files and Windows 2000/XP hibernation files (where system memory is saved when you hibernate a laptop).
 

PC Pitstop (4/5)
Test the entire system performance, internet speed, disk health and check for Active X & Gator.
Works preferable with Internet Explorer but also with Mozilla and Opera after installing a plug-in named Neptune. But... they ask you to turn off the firewall. I did the anonimous test,... worked fine. They also try to sell you some product,... but all works fine even if you decide not to buy anything. Oh,... yea. They also check for virussen & spyware.

Autoruns (ONLY EXPERTS)
Shows you what programs are configured to run during system bootup or login, and shows you the entries in the order Windows processes them. These programs include ones in your startup folder, Run, RunOnce, and other Registry keys. You can configure Autoruns to show other locations, including Explorer shell extensions, toolbars, browser helper objects, Winlogon notifications, auto-start services, and much more. Autoruns goes way beyond the MSConfig


MoveOnBoot (ONLY EXPERTS)
MoveOnBoot lets you Move, Copy, Rename or Delete files on reboot before Windows can lock or alter them. (Requires restart of your system after you give MoveOnBoot instructions). This is a simple 3-step process. (Alternative download)
MoveOnBoot (stand-alone) is freeware, but also part of a payware suite: Gibin File Utilities.

What if You can not delete a file by a reboot. Windows says: file access denied, file in use error.
More information on softwarepatch.com