Win 98, eh? Anything past win ME i am less and less familiar with. BTW, I also got a controller card, and after a few hours of messing around with it and reading forums, no luck. To stay on topic, I have no idea on how to restore the registry in windows 98, ME and newer have an option in safe mode to restore to an earlier time. Have you tried reinstalling the drivers in safe mode?(F7) Does your computer go anywhere past the bios, into booting anything? If you think it might be with the controller card, see if you can just run the hard drive from the motherboard controller.