Device manager blank after SP2 Installed

I have had a problem with several machines of different spec after i install service pack 2 in windows XP. When i go into device manager the screen is blank. I checked on the Microsoft support site and the only relevant thing i found was to do with the plugandplay service might have stopped but after checking my machine the service is on.
Also the machines decide there is new hardware to install and there has been nothing added to the machine.
Any help would be appreciated as it will save me a rebuild.

 

Go to the link below, scroll down to line #107 and try the fix listed on the right-hand side, Restore the Device Manager.

http://www.kellys-korner-xp.com/xp_tweaks.htm

Save the REG File to your hard disk. Double click it and answer yes to the import prompt.

Steve