This got me thinking...why not use the collective wisdom of Speedguide members and create the ultimate PC tweak guide? I know we have a lot of smart people here, and I'm sure you guys have found tips and tweaks over the years to boost general PC performance, so why not post it here?
After following all of the tweak advice given on the forums...After pimping out your internet settings...After downloading the latest firewalls, antivirus programs, and spyware programs (Spybot, Ad-Aware, and Spyware Blaster are a great combo in my opinion

I am not an expert, but I do have a few basic suggestions that I have given to people in the past.
The stuff below is what I have done to get a general performance boost on my PC. Remember to backup all of your files and programs before tweaking your computer. I also recommend creating a system restore point before doing any serious tweaking. This probably isn't necessary, but a little safety never hurt anyone.
The first thing I recommend is turning off the flashy, mostly unnoticable garbage in XP that hogs CPU time and slows you down. Do this by right clicking on my computer, properties, advanced, performance settings.
Choose "best performance", and then click only the boxes for drop shadows and font smoothing. Leave everything else empty and click apply. For your desktop background, use a simple bitmap if possible, instead of a large picture from the internet. Those pretty pictures can take up 3-10MB of RAM just sitting there. If you want to maximize performance, find a smaller texture and tile it instead.
Next, open control panel and find the fonts folder. Get rid of any unnecessary or unused fonts you have in there. I recommend creating a new file on the desktop called font backup, and simply move every font you don't want into that file for safe keeping. Trimming the font folder in control panel to an absolute minimum can boost startup time because XP likes to load every single font into memory during the startup process. If you don't want the fancy fonts to load, get them out of that folder! (and move the folder off your desktop to save space, along with any other unused folders or icons)
I also recommend that people download a few nice free tweaking utilities. Two great freebies are TuneXP and X-Setup (the best!).
TuneXP can be downloaded here:
http://www.download.com/TuneXP/3000-208 ... d=10290928
and X-Setup Pro
http://www.majorgeeks.com/download.php?det=127
These utilities can make it very easy to tweak system settings, defrag the boot sector of your hard drive (fast booting!), and to disable the things you don't use (messenger, etc). The programs edit the registry, so if you decide to tweak, be careful with them. If you don't know what a setting does, don't change it! The programs have help files to consult. If you read files and use the programs properly, they should give you a very nice overall overall performance boost. In addition to the freebies, I also HIGHLY recommend the shareware version of TuneUP Utilities (http://www.tune-up.com). It has a very nice one-click maintenance icon to fix problems with applications along with several extra tweaks and optimization tools that I find very helpful.
I personally have disabled the paging file on my computer, but if you have one (by default, you should), you may find this utility useful. It defragments your page file at reboot...very nice, and free!

http://www.download.com/PageDefrag/3000 ... 47422.html
Next, right click on my computer. Choose properties, advanced, performance settings, advanced, then choose virtual memory. Change the minimum/maximum settings to a single static number. Keeping the paging file at a constant size prevents Windows from resizing it every few minutes, saving CPU time. XP recommends you set virtual memory at 1.5X your RAM, but if you have more than 2GB, you can probably safely disable the paging file. This will give a nice performance boost.
Also, visit http://www.blackviper.com to find out about any unnecessary services running on your PC. There is a LOT of unnecessary junk starting with Windows by default, and he explains how you can disable the services you don't need running. Also make sure to check out his "XP Super Tweak" section for a few extra system and security tweaks. I also recommend you copy his XP service configuration guides to a document on your PC. If anything goes wrong and you can't connect to the net after disabling certain services, you can always refer to the document and figure out how to put the defaults back in place to get up and running again.
There is another little trick I found. You can use this if you are simply on a home computer and are not attached to a local network. Open control panel, folder options, view, and unclick "automatically search for network folders and printers". This should speed up the loading of icons on the desktop and inside folders.
Another great little utility is called CCleaner (http://www.ccleaner.com). It quickly clears out unnecessary temporary files from internet cache and other areas. It is very fast, and I use it every day to clean things up after surfing the web.
After cleaning out all of the crap from your computer, update your antivirus/anti-spyware programs, then reboot into safe mode. In safe mode, run each antivirus program on the most thorough setting possible. Kill all of the viruses/spyware on your computer, then defragment your hard drive (start, programs, accessories, system tools, defrag). Next, use TuneXP to clean out your prefetch folder and do a boot defrag. If you have a paging file, set the page file defragmenter to run at next boot. The Tune-Up Utilities program also has a nice registry cleaner to clean out unnecessary junk and invalid references in your registry. After cleaning the registry, run the TuneUp registry defragmenter to defrag everything in the registry and reboot.
Done!
This should get you started on the road to the ultimate tweaked machine.
Less junk in your hard drive...less junk in your registry...a clean paging file...everything optimized for fast access, fast booting, and better performance.