Malware Or Adware - Page_fault_in_nonpaged_ Area

I had some malware or adware that I got rid of , I think. In the process, I may have made a mess of things and now I have this blue screen appearing regularly with the message: "page_fault_in_nonpaged_ area " along with some instructions to disable bios memory options such as caching and shadowing and it often reloads. There are also some 0x00000050 type numbers that change each time.I also upgraded to service pack 3 with no change.I can usually hit function 8 and I am back in business unless I let the machine sit idle when the blue screen reappears. I reinstalled XP with no different results.