Cleaning up my younger brothers computer has proven to be a harder task than I imagined...
Whatever viruses he has limit me from using AV programs in anything but safe-mode, won't let me install KIS, and closes my Firefox instantly, whilst slowing the computer to a snail pace.
Logs included, any help is appreciated.

For some reason, I can't even install Super Anti Spyware, so I'll try and get that log later.

First, take action on the things found by Malwarebytes. Delete these things, then post another hijackthis log