PC sputtering after a few minutes after boot

I was hoping someone could help me. I just built a new machine and after only about a month of use I think I've developed a virus. I'll admit I got a bit lazy about downloading an anti-virus and now I'm paying the price. The problem seems to come about half an hour after booting. the computer starts sputtering and freezing up for about 3 seconds every 10 seconds the cpu usage spikes up to about 28% every time it freezes. The day it started happening I installed a wireless card, I also downloaded MSN messenger, installed it, and downloaded a driver for my Razer Tarantula keyboard. I've tried isolating these things to see if any of them are causing it but I can't seem to single it down to anything. Here is a hijack this log... I will be extremely grateful if someone can help me

Logfile of HijackThis v1.99.1
Scan saved at 9:45:10 PM, on 7/25/2008
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16674)


PLEASE HELP!!! I've got a commission job I have to finish this weekend and I can't do it with a sputtering system. If anyone can suggest a good free firewall I'd also be extremely grateful.

-thanks in advance

 

Welcome to Major Geeks!

Please follow the instructions in the below link and attach the requested logs when you finish these instructions. If something does not run, write down the info to explain to us later but keep on going. Do not assume that because one step does not work that they all will not.

READ & RUN ME FIRST. Malware Removal Guide


Note: If you run into problems trying to run the READ & RUN ME or any of the scans in normal boot mode. You can running steps in safe boot mode but make sure you tell us what you did later when you post logs. See the below if you do not know how to boot in safe mode:

Starting your computer in Safe mode








(Note: Freeware firewalls and anti-viruses can be found here but you need to get your PC clean first)