Virus Help

My computer definitely has some kind of virus, but I can not seem to get rid of it. I was running ESET NOD antivirus on it; however the virus has bypassed it. Whenever I try to run it the computer freezes. I can not open the task manager because when I do the computer also freezes. I have tried to install other anti virus but it doesn't work. I thought I had the sasser virus because I always get lsass.exe problems; however I tried the fix on the microsoft site and it didn't do anything. I ran stinger but it did not find anything. I am writing this from another computer because whenever I type something related to the virus into the computer it freezes. Other errors I get are msiexec.exe and dr. watsons debugger. I have recently started seeing data execution prevention. Sometimes everything just disappears. I renamed Hijackthis. I can run it, but when the scan completes it does not save a log it just freezes. Any help would be appreciated.

Thanks
Jon