I had the same problem, tho it was an actual defective CL card. Make sure if you've ever had a Voodoo card installed on that system that you've manually wiped all the data off the HD. To do so, just goto find files and type in 3dfx.*, then search, delete everything, then search for glide.*, and do the same thing. Also, might want to check for voodoo.* as well. Next, make sure you have the most recent drivers, and also make sure your system isn't running to hot. Hope those help.