You might have had a power surge or something which corrupted some of your drivers since you say you had to reinstall your mouseware etc...
Go into your hardware devices, locate your audio and remove the drivers. Restart and let windows redetect and install fresh ones. Make sure your card (if not onboard) is seated properly. If it is onboard, make sure it is enabled in your BIOS.
My gaming machine:
P4 2.8 GHz
2 X 512 MHz PC3200 in dual DDR mode
Intel D865PERL MOBO
integrated 6.1 MAX audio
Logitech duo MX mouse and KB
ATI RADEON 9800 PRO