In My Computer click on Tools then View and tick to Show hidden files and folder" then untick "Hide protected system files and folders". Accept the warning, click on Apply and OK your way out.
Navigate to the Windows folder and copy the Inf folder to an external source. Then go to Windows\System32 and copy the two folders, Drivers and DRV_STORE to the same external source.
Back in the root of C:, look for any folder named after the computer manufacturer and take a copy of that. Parachute those into the new installation before you ddo anything else - updating to SP3, etc. and you should be OK. Any stragglers can be tracked down on the Net.