After Vista SP1 installation, on  reboot, USB Connected Mouse or Keyboards fail to work.

Resolution:

1)    Boot to WinRE and run a System Restore to uninstall SP1 (try a date when the SP1 upgrade wasnt done)

If the Issue is not resolved by Step1 then try Step2

2)    Boot to WinRE >> Command Prompt

At the x:\sources prompt, run the following commands:

C:
cd\windows\system32\config
ren system system.old
copy regback\system
ren software software.old
copy regback\software

Where C: is the drive letter of the partition where the os in installed.

If the Issue is not resolved by Step2 then try Step3

3)    This time copy hivename.old into the config folder. To this follow these steps.

From the x:\sources prompt, run the following commands:

C:
cd\windows\system\config
ren system system1.old
copy regback\system.old system
ren software software1.old
copy regback\software.old software

reboot the system, USB will work.
Where C: is the drive letter of the partition where the os in installed.