Overheating Geforce 256 SDR???

I had a Geforce 256 that ran in my MSI system and I had no problems with it. I even had it overclocked to 150/200. Now my brother has it in his system witch is a K6-2 500 in a gigabyte board. Now his puter will freeze after it gets into windows. He put a BIG fan blowing on the card and that is the only way it will work. BTW it is not overclocked anymore. We checked the heaksink and fan and they seem to be fine. What could it be? It doesn't feel that much hotter to my finger than when it was in my system.

Will the system boot into the system with other video cards? IT doesn't seem right tht it just won't boot..

No it will boot, just it crashes once it is in windows. And BTW with the big fan it runs stable. His puter had a voodoo 3500 in it before and ran fine. It just shouldn't need a huge fan on it running at stock speeds.