Ok I mentioned in that "ouch" thread that I would post my XP tweaks. Now please keep in mind that some of these may not be for everyone. Just think of it as a buffet of tweaks that you can pick and choose what works for you.
here is a list of services that I know for sure are safe to stop and disable. Some of these services you may use depending on what you do with your pc. I can tell you that if you game, surf the web,check email, do homework or programming that these will not have a bad effect for you. These are services that I disable in XP pro, so if you have Home and dont see some of these dont worry about them.
1.
automatic updates: If you know how to check Microsoft's web site for patches periodically, then you dont need this.
2.
Help and support: this contains windows help fles and services. If you are confident that you can solve windows and hardware problems on your own, then you dont need this.
3.
Indexing service: This basically allows you make fast searches for files. Searches wil just take a little bit longer without it.
4.
Messenger : This one everyone should disable. This is the sneaky devil that pops up those irritating windows messenger popup spams during your gaming sessions.
5.
Netmeeting remote desktop sharing : Unless you want people to be able to remotely access files on your computer, you can disable this.
6.
Remote registry: Unless you want someone to be able to remotely access your registry(you dont...trust me) you can disable this.
7.
Routing and remote access : More remote access stuff. Just disable it.
8.
Smart card : If you dont use smart cards or plan on using smart cards, you can disable this.
9.
Smart card helper: If you disabled smart card then you can disable this.
10.
system restore : If you have a habit of messing up windows, you should leave this alone. It will restore your system to the last known working condition. Advanced users can disable this.
11.
Task scheduler: If you dont have your system perform scheduled maintenance, you can disable this.
12.
telnet : More remote access stuff. If you dont know what it is, you can disable it.
13.
Themes:this service is what makes xp all pretty looking.

If you dont need that, then you can disable it.
14.
Uninterruptable power supply : If you dont use a UPS or battery backup, you can disble this.
15.
wireless zero configuration : If you dont have a wireless card installed, you can disable this.
16.
Nvidia driver helper service : Just disable this
17.
portable media serial number If you dont use any portable music devices with your computer such as mp3 players, you can disable this.
Ok, here are some other windows tweaks I do:
1. delete as many icons off the desktop as possible. Dont delete recycle bin.
2. Remove as many of the icons fron your task bar as possible. These startup with windows and slow the process down.
3.Remove your background if you dont really need or want one. This will free up a small amount of memory.
4.defrag your hard drive regularly. If you are constanlty deleting and installing files, this needs to be done.
5. Do not download free programs that are loaded with spyware and adware. Avoid these like the plague.
Here are some bios tweaks:
1. disable onboard features that you dont use. If you dont use usb 2.0 disable it. If you dont use your serial ports disable them. If you dont use your parallel ports disable them. If you dont use serial ata, disable it. If you dont use your onboard lan, disable it. If you dont use your onboard sound or video, disable them. If you dont use infrared devices disable the IR port.
2. disable hyperthreading. I find that for games it is actually faster to have HT disabled. HT is only faster for multitasking.
well thats all i can think of right now.