How can i copy MSVCRT.DLL to winnt\system32

Hi, I would like to copy the file msvcrt.dll from the win distribution oh php4 to the folder winnt\system32 as said in the readme.txt that comes with php-4.0.3pl1-Win32.zip When I try to paste the msvcrt.dll from the distribution into winnt\system32 I get a message saying that the file is in use and it can not be deleted. I tried to end all the processes running but I could not find which process is using that .dll. I tried to copy that file being loged on as administrator. The partition on which nt is installed is on ntfs so I can not boot with a dos disk in order to copy the file as i could in win98 or win95. In fact I would appreciate if anyone could tell me which is the right way (or just way) to update a dll file (or anyfile) when it is used by a task/process that I can not end. Thank you, Catalin