✔ 最佳答案
Possible cause: Corrupted sound card driver.
The easiest way is to restore your laptop to a previous date when the sound card driver was working.
In XP, (Vista, Win 7 similar) go through:
Start \ All programs \ Accessories \ System Tools \ system Restore.
Click to open Restore window. Click Restore my computer to an earlier time. Click on the latest date in calendar with Bold numbers. For example, 8/5/2010 is the latest to 12/5/2010. Answer Yes to restore. Windows will run then restart to the status on that day. Now try the sound and see if it works. If it doesn't , go back to the next latest day, say, 4/5/2010 and see.
Note: Windows automatically records dates randomly in background for you to roll back in case something's messed up in the system (like yours). You'll lose all programs installed after that day but not your work (files, etc). So judge you benefits against the risk.
But I guess it's worth to try in your case. Looks like all laptop manufacturers have a copy of your Windows system hidden in a partition in your hard drive. They normally tell you to make a copy onto a set of CD's when first purchased for future repair. If you haven't, read up on the internet.
Good luck.
2010-05-12 15:21:31 補充:
Last of all, tell us whatever happens to your restore.