Sound Card not recognized after reboot

I have a Yamaha Sound card OPLymf715b-s. After installation it works fine. When I reboot, it is not seen. If I go to Add New Hardware, it finds it right away and works fine but I have to do this everytime I turn on the computer. There are no conflicts in Device Manager. I’ve tried putting it in a different slot. The auto detect is on. I tried another sound card and it did the same thing. I tried it in another computer and it works and holds it’s settings fine. I even installed a modemand that works fine and keeps the settings after rebooting. Everything else works fine. Only the sound card is giving a problem. It doesn’t matter, if its PCI or ISA. Pls. help.