If you have a need to monitor activity on a computer - there is a an easy solution. All you need is one of these:
It is the Stealth iBot Deluxe. It can pretty much tell you everything that has gone on the computer. It works like a memory stick. Plug it in to install the software. Unplug it and wait. You get notified of activity on the computer by email. You can also go back and get every bit of information and activity that goes on.
This is what they say about it:
The Stealth iBot Deluxe logs every keystroke typed from chats, Instant Messages, search engines, emails and control fields exchanged with your child, teen, spouse or employee. The software will also capture screenshots that you can set to meet your own monitoring preferences, like keyword/keyphrase triggers, which will send alerts to your email every time the keylogging software detects a word you've selected to monitor.
Whatever you do - Stay Safe!!