Sometimes you need to replace damaged system files with correct ones. I’m talking about files in C:\windows\system32\…
There are 2 ways of doing this:
Use sfc command: insert distribution disk with correct version of Windows, execute sfc /purgecache to clean out the cache of drivers/files. Then execute sfc /scannow. This will check all the system files and replace damaged.
Another way is to replace files one by one. Again, insert your distribution disk, then run command:
expand D:\i386\ndis.sy_ C:\windows\system32\drivers\ndis.sys
This unpacks compressed files from the CD archive.