I have another suggestion, though it is unlikely. It could be that your sound card is slightly out of the slot. If you have an onboard sound card, feel free to ignore the rest of this completely.

I sometimes have this problem when I mess around inside my comp, but the sound card is kind of in a strange position and the far end can come out and thus when I restart my computer there is no volume control, or any sound for that matter, since it wasn't detecting that the card was physically there.

The reason games may not work is because it is trying to start the game when there is no sound capabilities, and thus it generates an error when it tries to load anything sound-related. I know in Jazz2 you can get passed this by setting an option at the command line. I myself used to experience this and the whole thing resulted in making a program that I uploaded to J2O called Jazz2Debugger or something like that. Basically all it does is make using the command line options for Jazz2 easier, and in there is an option for Jazz not to start up any sound devices. Using this you would probably still be able to play, just with no sound.