Not exactly to do with Windows games but Windows itself.

I supplied a computer for my sisters to use for their own games and surfing the web etc. They originally had a 150Mhz board. I decided to switch it with a 233 MMX board I had so I could keep the old one (I like the old stuff). So I took the board out and put the new one in and replaced all the cards that were in there and everything and tried to start up Windows 98 (that was already on the HD) and it said there was some kind of error in SHELL and said the computer had to be rebooted. It would go into safe mode easy enough, but even then everything there started performing illegal operations and crashed until Explorer itself crashed and all I was looking at was the background and it would do anything else.

So I thought that if I reinstalled Windows it would fix itself all up. I was wrong. Now since I've reinstalled it it won't even go into safe mode (it automatically reboots the computer and then says there's an error in SHELL again and it tells me to reboot). It's a vicious cycle. Now I'm thinking there must be some setting on the new motherboard's BIOS that has something to do with it but I have no idea what. Does anyone here have any ideas?