Installing SP2 and having problems with atapi.dll

The backup process of SP2 can hang when trying to read the file c:\windows\system32\drivers\atapi.dll - the backup utility says it can't find it yet you can go in the folder and see it is there.

The reason the file cannot be accessed is because you are using it in the system.. duh.

To find out what process is using this file download http://www.sysinternals.com/Utilities/Handle.html
Start a command prompt and type

> handle atapi
System pid: 4 1384: C:\WINDOWS\system32\drivers\atapi.sys

The answer was process id 4, the "System", next you can kill that handle:

> handle -c 1384 -p 4
Handle v3.11
Copyright (C) 1997-2005 Mark Russinovich
Sysinternals - www.sysinternals.com

1384: File C:\WINDOWS\system32\drivers\atapi.sys
Close handle 1384 in System (PID 4)? (y/n) y

Handle closed.

There you go... you can now continue with what you where doing... but remember to restart as soon as the SP2 install is done, you have most likely upset your system by removing the handle.