1. I was able to stop and restart 'windows audio' but I was not able to stop or start 'plug and play'. Should I restart the computer?

2. I tried registry cleaning.

3. I don't think I've integrated any audio devices, but I'm not sure if I have add-in sound card too. How can I check if I have one or not?

4. I have no idea what is a overclock...or overclocking..

5. I don't think reinstalling windows will solve it, because upgrading my computer to Windows 7, I still had sound problem in Windows vista.