I've been struggling with this issue for weeks now. Every time I try to open Movie Maker (or any other Windows Live Essentials program) I get this message:

"windows/system32/mf.dll is either not designed to run on windows or it contains an error"

and it suggests I try reinstalling to fix the problem. I've uninstalled and then reinstalled multiple times but the same error keep occurring. I had been using the programs with no problems whatsoever until one day this error popped up. Please help.