Can someone help with my computer performance issue?

I have an Alienware Aurora 7500 I bought back in January (amd athlon 64 x2 5200+, nvidia nforce 590 sli, 512MB nvidia geforce 8800GT, 2GB DDR2-800 RAM, 320GB Hard Drive w/WinXP Home). I play high performance games on my system, but recently (2 days ago) my computer stopped working at it's best in-game, and even if I turn down the resolution and graphics, it plays the same. For example, Call of Duty 4 will only utilize about 600MB of RAM and 85% of my processor, but it will skip uncontrollably. What changes need to be made?

Can someone help with my computer performance issue?adware

A lot of people don't know that adware/spyware can get into your computer (and some noobs think that using Firefox stops you from being able to get adware/spyware).

The fact of the matter is that since so many people are using Firefox now, "hackers" are writing adware/spyware for Firefox too.

Download and run Spybot Search and Destroy 1.5:

http://www.safer-networking.org/en/index...

Download and run Lavasoft Adaware 2007:

http://www.lavasoftusa.com/

If you use free antivirus programs (especially if you have AVG Antivirus), upgrade to Avast... (Avast is free for home users):

http://www.avast.com/eng/avast_4_home.ht...

If you pay for an antivirus, upgrade to NOD32. It's the best antivirus around.