Tnx..when i try to boot into anything, the pc hangs. i'm not sure what it tries to do and fail but i suspect it needs to write to RAM and can't. When booting from a Ubuntu CD, the GUI show for a bit then it tries to fully boot into the system and i get a flashing cursor and black screen hang. W98 boot diskette, wxp install cd, dell utility cd....the bootup process either hangs or when I select a boot option the system reverts right back into a new POST like in a loop. I've swapped mem modules...not sure what this could be.
Do you have a spare Power Supply to try swapping in? This could be an issue. If that doesn't help, your motherboard is most likely going bad. Luckily they are not too tough to find for that system.