nogo on the malwarebytes.
I can download on her computer, but it won't run. Tried renaming it at the downloand and at the desktop, nada; the false security suite kicks in and won't allow MWbiytes to run its set-up.
I found something about roguekiller first, then MWbytes?
http://forum.avast.com/index.php?topic=74898.0
Are you in safe mode when trying to install it? if not, boot into safe mode and see if you can install it then.
You also shouldn't be connected to the Internet on that computer any longer. Only connect to the Internet as absolutely necessary (to download definition updates and removal software) after that disconnect right away.