Fix Sleeping Problems with Windows Vista
I hope this is an OK place for this post. Just spent a long time trying to sort this out and finally found the solution in Google after running down countless dead ends.
If your Vista PC won't sleep some of the time, it just hangs when the new hybrd sleep mode is writing the RAM contents to disk, and you have to hard boot, try this:
"Start" > Control Panel
Go to the Hardware tab
Go to the Power Management tab
Clear the Allow this device to wake the computer checkbox
I first tried disabling wakup by device in the bios, wake on lan in the network adapter settings in windows, different ACPI modes in the bios, and none of it made any difference.
The reason the problem was intermittent is because only some of the time did the mouse get moved during shut down.