It seems that upgrading the powersupply to the power hungry desktop system is not enough, although I still believe that it helped to some extend. However, it would appear that my 2x512MB memory sticks are the culprits.
Microsoft's memory test program froze while testing them. Perhaps I'll test them one by one and may have to settle with just 512MB for the meantime.
I've heard stories that memory problem could even be caused by improper motherboard installation, for example, motherboard part touching tower metal thus creating unexpected voltage vs current hence problem.
I do not have time to look deeper into these right now, as long as I don't run memory hungry programs on this system, it barks like a nice little puppy.
[@more@]