Hard lock problem....

Cel 300A @ 308, 256 MB RAM, Soyo MB, dual boot Win95 OSR2, and Win2K. Occasionally hard locks in both OS's, and getting worse. Did it three times last night, in the space of an hour. I can't move the mouse, and CTL-ALT-DEL doesn't work, either. Have to hard reset. I haven't tried changing anything yet, but my first thing I'm going to try is to swap the RAM with what's in my Linux box. If that doesn't fix it, I'll swap the MB with one a friend has. Just in case that doesn't do it, are there any more suggestions of what it could be?

(I know, I should just buy an Asus or Abit MB, and a 1.2 Palomino, but I'm hoping I can get this POS going again. If I get anything any faster, I won't be able to play Jazz Jackrabbit! )