Then, if you're using a Pentium 4 with hyperthreading, it might be a good idea to turn off hyperthreading at the BIOS level. I have had experiences with applications going invisible - WinAmp, w.bloggar, and some home grown stuff would start and would work, but would not be drawn to the screen. I was unable to find any good reason for this until one of my coworkers suggested hyperthreading as the culprit and lo and behold it seems - at least on one of my systems - that if I turn off hyperthreading the problem is gone.