Removed hotfix 890859, USB mouse + keyboard don't work upon logging in.

Hi there, I will give a run-down of the problems that have arisen recently.
Windows\system32\config\system corrupted or missing - ok managed to fix that by taking a copy from a restore point.

Works ok for 1 boot, then apparently crashes and the same error arises (I was not present when this happened, so I'm not sure of the exact details.

Tried to fix again by following the same procedure, except now it XP can't find any of the restore files. Fixed once again, now I thought I was getting somewhere.

Oh how wrong I was....
Now upon start up I received a blue screen error code : c000021a .
Narrowed it down to a hotfix error thanks to some forums and so removed the hotfix from the recovery console.

Now it finally manages to logon, at last I thought I could get my data of it and re-install / re-format completely. But once again, I was foiled in my efforts.

As unfortunantly the USB mouse and keyboard didn't respond at all.
They say that these system operate on the GIGO principal, but I would currently give anything even if it was from the virtual rubbish bin!

And now I have gone back to the original error, though I should be able to sort this part of it farily quickly.

In short, I think I need to re-install / repair the USB mouse + keyboard drivers?
Probably by transfering them from the repair folder as i did with system.bak, software.bak etc?
But I'm not sure, and the nearest I could find on the microsoft support site was for Windows 2000 which achieved nothing when input + modded a bit in the recovery console.

Any help that you can possibly give or even links to other posts/sites detailing simmilar problems would be greatly appreciaited :)

Thanks in advance for your help,

Alex