Take out your memory and have it tested at a local shop or use a DOS based hardware checker program, sounds like you might have some bad chips. Are you using older hardware? First time I installed 2k server was on a dual pentium 233MMX Socket 7 machine, had lots of probs.
I recently installed 2k server on my new box which has 500MHz CPU & 256megs memory. 2k regular server edition creates some kind of index file the just WOLFS up GOBBS of memory (commit charge was well over 300,000) and causes excessive paging for about 5 minutes. Advanced Server doesn't have this problem, don't know why. A typical install of Adv Server will chew a 100megs at startup and go from there.
Please keep in mind that MS says that 128megs is minimum for server and recommends 256megs. I say 1/2 gig is closer to reality.
2k doesn't like AMD CPU's or VIA chipsets either, I ran into that prob couple months ago on a contract gig. They have a program on their web site which will check your hardware and identify potential issues.
Good Luck
Bruce,MCSE