Personal space at work?

What has me concerned most of all is the fact that someone has been using your computer. I'm uming it's pword protected and that you lock your computer every evening? You should address this issue with your supervisor or manager immediately. This could be cled as a security breach. And absolutely talk about your other issues. Whomever is messing with your desk is interfering with your ability to do your job. You need to speak up as soon as possible.