PC doesn't detect my sound card , what could be wrong?

[calmius]

Here is what happened.
I turn on my computer after I get home.
At the desktop everything freezes. I restart.

After restart there is no picture. Turned out the video card wasn't sending any signal. I remove the video card. Try another video card. everything works. But old one back in, and it works again.

The same thing happened with my sound card. The computer doesn't detect it and switched to its motherboard processor. I tried to remove the sound card, restart computer, then put card back in. Still it doesn't detect it. When I try to install drivers for it, software says no needed card is detected.

Any idea why both the video and the sound card could have stopped working after my computer froze. And how could I make my computer detect the card again?

[glc]

Full specs, please.

[calmius]

Originally Posted by glc Full specs, please.

cpu - 2.4ghz Intel 478pin
mobo - Asrock
ram - 1gb rdram
video card - GeForce 6600 Gt
sound card - Audigy 2