in the period of about 1-2 hours after I started my computert, everything was normal, then a weird phenomenon happened, the computer became very blunt, mouse moving was extremely slow, every process closed to the edge of cease. I re-installed the operating system( win2k pro), it did not help it, also checked whole files in my computer by Norto Antivirus, no virus found....checked all processes which was running at time time by "windows task manager", found a process named "ifk.exe" occupied 99% resourse of CPU. So, stop it, all things turned back to normal again... I'm trying to delete it, but I cannot find it, even use windows search engine to scan all files. it's strange.

somebody can help me to deal with this proble. I think maybe some kind of virus Norton Antivirus cannot detect.