It starts the scan but then it states there is a problem with the program and the program must close. Why is this? What can I use instead? I want a free download if possible by the way.

Answer:
TweakNow is rubbish. I'd recommend using the free program called “ccleaner”.

http://www.ccleaner.com/

Answer:
tweaknow is known for issues like this

use ccleaner and these others from http://www.freewarefiles.com

regscrubvistaxp, argente registry cleaner, glary utilities

these work and are very effective

Answer:
ccleaner is a great little programme

http://www.ccleaner.com/