Windows 7: Cannot wake up computer

After Windows update on 01/16/11 I have been unable to wake up my computer with the mouse or the keyboard. So I have to manually shut down windows and I get the warning screen that Windows did not shut correctly. I am not sure though it was the update that caused the problem but that's when it began and I have not experienced it prior. Any help would be greatly appreciated!

Use this tuturial to check hibernation settings and to disable it.

Hibernate - Enable or Disable[2]=Power Management

If you cannot wake up, why do you need to shut down? I cannot understand what you are experiencing.

System Restore to before the Updates: System Restore

Then install each update until you find which one caused the problem, open a Support case on Windows Updates website. Support is free and by email.

Right, Karma, I wasn't totally clear about what was happening. I would leave my computer, assumed it went to sleep but when I came back everything was frozen (lack of a better word) so I had to manually shut down and reboot so that apps would work, etc. Since my last post Microsoft updated Microsoft Security Essentials and most everything is now working like it did prior to the 16th of this month. The only thing now is that the hard drive doesn't shut down no matter what power settings I choose but I guess I'll live with that for now.