Updating windows registry
If all updates are installed (or if you have troubles with the Windows Update website), you can safely delete the files in the following folders: C:\Windows\System32\Catroot2 C:\WINDOWS\Software Distribution\Download I can't imagine you would like to roll back the installed high priority Windows updates, especially if there are no problems.
Updating Windows is actually very easy, first you visit the Windows Update website: Start, All Programs, Windows Update (or visit the Windows Update website with the following link: windowsupdate.microsoft.com).
After you installed the high priority critical updates, restart Windows and visit the Windows Update website again.
These updates can be massive, especially if service pack 3 is not installed yet.
That's why you better install one device driver update at a time.
If the new driver is giving a BSOD (Bleu Screen Of Death), boot in safe mode (press F8 at reboot), Control Panel, System, tab Hardware, button Device Manager, right click the updated hardware, select Properties, tab Driver, button Roll Back Driver.
Search for updating windows registry:
If resetting Windows Update didn't help, resetting the Internet Explorer settings might do the job (Tools, Internet Options, tab Advanced, button Reset).