Do what everyone else does. You use MoveFileEx to get the files copied to the correct places during the system restart. Prior to restarting, add a RunOnce program that will register the DLL while the system is starting up. Tell user to reboot system. This is the 'recommended way to repalce DLL that are in use. Look at all the MS security udpates, constant reboots of machine, eh? Works for them.. should work for you!