After another question about something like this :
"i've deleted a file in Winnt or Winnt/system32, it worked but the file is always here (w2k system)", i decided to wrote this :This is only apply to Windows 2000 and XP and can save you from some headaches
Under Winnt/System32/dllcache (compressed on NTFS), you have most of the file in winnt, winnt/system32 and winnt/system32/drivers
An internal service which is running permanently, monitor change that can occurs in the Winnt folders and subfolders. If a file is changed and does not have same size and/or version than the one with the same name in dllcache, it is immediatly replaced (and registered) with the one from dllcache. The only thing that let you know about is a new entry in the System log (Same occurs if the replacement fails). Good bye dll hell
For now, i didn't see any problems with this methods, unless you want to remove some unwanted files. In this case, you must remove the file from dllcache FIRST, and after the one at the original placement
Also, you can change the placement in GPO, but never put it on a network drive (windows must have it before login occurs)
For more informations :
MSDN:Windows File Protection
Windows Registry
[ 28 December 2001: Message edited by: Alex.H ]