Hi Roger,
Please test the issue in Safe Mode. Can we shut down the computer in Safe Mode?
If so, I suggest tying Method 1 in the following method to perform a Clean Boot.
How to perform a clean boot procedure to prevent background programs from interfering with a game or a program that you currently use
http://support.microsoft.com/kb/331796/en-us
If the issue does not occur after performing Method 1, we can try Method 3 to find the cause of the issue.
If the issue also occurs in Safe Mode, I suggest restoring the system to a state when the issue did not occur. Then reinstall these updates one at a time to find the problematic update.
As for the sound issue, I suggest installing the latest sound card driver.
Hope it helps.
Tim Quan - MSFT