If this is your problem, this will get the ball rolling in the right direction.
There are some that speculate that perhaps your "PC's CPU is wasted by lots of non-essential Windows stuff." 1) This reminded me of an article that I read in PCGamer UK edition, Febuary 2007 no 171 on page 116-117. If you don't buy that magazine or don't give a fig, not to worry - I have no life. Short recap:
* You can take controll by either going threw the startup files manually and then close anything that demands processing power every time you want to game, or
* Make a new profile and just make a "clean boot" standard
I run Microsoft XP Home edition, so I made a profile called GAMING.
Click on START, and then RUN. Type in msconfig
Click on STARTUP
Uncheck the necessary files
Now, I know what you are thinking. You a moron or what? There are lots of fancy FREE programs out there that can do this better. Yes; I would advice RegCleaner. Just google "regcleaner+download" and you find a bunch of websites where you can get this baby. It even makes that handy backup incase you mess up unchecking one of those critical files. Or, you might be thinking that I'm still a moron, cause ...
how the f... do I know what is necessary file or not? Bi***!
Luckily, our pal Long Bow made a recogmendation for Tweakguides.com and you could do a search there. Or ... the magazine came with a handy little guide (what file is what) that I followed and had no trouble. As I said, I made a seperate profile with ONLY gaming in mind (for those games who demand an arm and a leg of your computer).
2)
These files you do NOT uncheck
The Clean Machine
RUNDLL32.EXE
This is essential to run dll files, a fundamental part of Windows' basic operation, so leave it be.
EXPLORER.EXE
The Windows interface, not the internet browser. Close this and lose your Task Bar.
SVCHOST.EXE
Handles processes started by dll files. Use Security Task Manager, downloadable at http://www.neuber.com/taskmanager/download.html to find out what it's really doing.
CSRSS.EXE
Client/Server Runtime Server Subsystem. Part of what makes Windows talk to your PC.
LSASS.EXE
Microsoft's Community Support Officer, lsass looks after local security issues.
I let some of the startups live. For example tuning the graphics for NVIDIA, the "trey" and button assignment for my mouse etc. Rest - BEGONE!
Be wee bit careful, one wrong turn etc ... otherwise I go with BEGONE method.
(1 and 2 =Direct quote from PCGamer Febuary 2007 UK version no 171 page 116-117)