The free program Treesize can be downloaded and run. It will show you everything that's on the computer. Re your brother, I think I'd password protect the computer so he can't use it. I'd also be sure to have everything backed up to an external hard drive.
I have a question. I have a work laptop that is only used at home, therefore I connect with my own modem. I use it for work, and occasionally facebook. I've had it for a couple of months now.
The other day, I opened it only to find a porn website live. I never knew, but my brother had been sneaking on for months to use it for porn. He always used Private Browsing. My question is, will this be shown at all?
I have used CCleaner, and deleted all history. Will it be shown on the hard drive? If so, how can I delete it and can work track it?