It sounds very much as though you need to restore your original sound card settings in your BIOS, though I'm surprised you were unable to fit your video capture card. The drivers should've been on a CD or floppy you received with it.
Sometimes these drivers load themselves but sometimes you have to go into your Device Manager and installing the drivers that way.
If you need to know how this is done come back and I'll give you my email addy when perhaps I can of more help.