Windows Tips Galore
Active Windows offers a first rate combination of tips and tutorials along with some useful reviews. The PCStats site features an excellent collection of Windows tips taken from the PCStats forums. I particularly liked the registry patch for removing those annoying entries in the "Add/Remove programs" menu that hang around long after the program has been uninstalled.
http://www.activewin.com
http://www.pcstats.com/articleview.cfm?articleid=1190&page=3

Tweaks for XP Freaks
We've mentioned this excellent collection of free Windows XP registry tweaks before but on a recent visit I noticed that it's now bigger and better than ever. Each tweak can be downloaded as a .reg file to save you the task of editing your registry.
http://www.kellys-korner-xp.com/xp_tweaks.htm

Windows XP Tips from Microsoft
Dozens of XP Pro tips including a sneaky way to bulk rename files. I didn't know you could do that in Windows. Guess you learn something every day.
http://www.microsoft.com/windowsxp/expertzone/tips/default.asp

Speed Up Your PC
This site offers a good collection of performance enhancing tweaks. I've seen most of them elsewhere but here they are nicely organized with many tweaks available as downloadable .reg files for those timid about patching the Windows Registry.
http://www.pureperformance.com/

How Fast do you Really Surf?
The high data rate you get when downloading a big file is not a
reliable measure of how quickly you can surf. This site offers a
free test that measures your connection speed to 40 different
sites worldwide. Be prepared to have your ego deflated ;>)
http://www.numion.com/

Mysterious Startup Programs Explained
If you've ever looked at your Windows startup folder you're bound to find a number of odd-named executables. Check out exactly what each program does at this valuable resource site:
http://www.pacs-portal.co.uk/startup_pages/startup_full.htm

Find Email Addresses
If you are looking for someone's email address, the bad news is there's no central directory. However this site offers a meta search engine that will search many possible sources. Quite to my surprise, I found my own personal email address.
http://mesa.rrzn.uni-hannover.de/

Commercial Software for Free
Many commercial software products started life as freeware. You can still locate many of these original free versions at the Internet Archive, which has captured snapshots of the web at different points of time for research purposes. Just enter the software vendor's web site address and with a bit of luck, you may be able to locate and download a free version.
http://www.archive.org/

BIOS Optimization Guide
Want to tweak your BIOS for maximum speed or stability? Like to understand the meaning of some of the obscure settings in your BIOS setup? If so, head straight to this site.
http://www.rojakpot.com/default.aspx?location=1

Organize Your Partitions Correctly
What's the best way to organize the partitions on your hard disk? Now that's a question that would take a long dinner and two bottles of red wine to sort out. For those who don't like wine or simply want a quick introduction to the issues, check out the following article.
http://aumha.org/win4/a/parts.htm

Optimizing the Windows XP Paging File
This is one of the best articles I've yet seen on this subject. It dispels many myths including setting the max and min sizes the same and setting the maximum size at 2.5 times the memory size.
http://aumha.org/a/xpvm.htm

Free Windows Networking Help
Got a networking problem? Want a networking tutorial? Need some background on Windows networking technology? Then head straight for this excellent resource site. The content quality is a bit variable but hey, it's free.
http://www.wown.com/

XP Questions Answered
This site offers an excellent collection of Windows XP tips including answers to some of the most common only encountered problems.
http://www.windows-help.net/WindowsXP/all-tips.html

How to Make Windows XP Run Faster
This site lists a step-by-step procedure for optimizing the performance of Windows XP. Most of it is good advice but comes at a cost in the form of slightly downgraded appearance and the loss of little-used features and services.
http://www.techreviewer.com/viewpage.cfm/pi/9

Impressive Windows Tips and Tricks Site
More performance enhancing and behavior modification tweaks than you ever imagined.
http://www.mdgx.com

More Networking Help
A couple of issues back I mentioned the excellent wireless networking resources offered by the Practically Networked site. This prompted subscriber Richard Cowper to write in about the Home Net Help site. Nice find Richard. The coverage is wider than just wireless networking too. Well worth visiting.
http://www.homenethelp.com/

Windows XP Tips Galore
The first link is to a site offering a nice list of 101 tips covering ways you can improve performance, increase privacy and more. The second link is another site which, rather cleverly, lists its tips in popularity order. Backing up/restoring/disabling XP activation topped the popularity list.
http://www.pcstats.com/articleview.cfm?articleID=1494
http://is-it-true.org/nt/xp/index.shtml

Windows XP Fix Zone
Another useful tech support site with a large collection of how-to articles, troubleshooting guides and customization tips. The site organization is a bit strange but that doesn't detract from the value of the content.
http://www.winxpfix.com/