This just happened last night. I have a 6 year old Compaq Presario (one of the worst computers anyone can get), 400mHz K6 processor, 64 MB RAM, Windows 98 First Edition.

I was chatting and browsing like usual, and one or more programs started making my computer go all grindy and unresponsive, which happens alot. I tried closing the programs and restarting, but the computer froze, which also happens alot. Then I switched the computer off in the back, waited, and turned it back on... which also also happens alot.

But this time, after the red-on-black Compaq screen came up, instead of going to the Windows splash screen, it immediately had a message that said "Program caused a divide overflow error. Contact program vendor if problem persists." (or something very similar to that). I hadn't ever seen that before, even after having switch it on and off like that probably a few hundred times.

I Ctrl+Alt+Del'ed to restart it, and it did the exact same thing. I put in my DOS boot disk and restarted, and it did the exact same thing. I even put in QuickRestore (the HD formatter), and it did the exact same thing. Then I tried all the other F- keys, and the only one that worked was F10, which seems to bring up the BIOS. That worked. But I haven't dealt with the BIOS before so I wasn't sure what problems to check.

I think it was the POST check that I changed to "full" that made it count from 0 to 65536 when I restarted, and it said something about the memory size being incorrect, I think. I messed around with more options for awhile but it never got rid of the "divide overflow error" on attempted startups.
I'm pretty much lost now. Someone suggested I remove the RAM stick and clean it a little, though I'm not sure that'd work. There's a chance that getting a new RAM stick in there would fix the problem, but I don't want to waste money on a wild guess like that. Has anyone dealt with this sort of problem before