Salem, thanks so much for a very detailed answer to my post, I am extremely grateful for the time you took to answer me.
So...it's easy for him to do this? Thats annoying beyond belief.
There is a box with a user name and password entry that I can find when I try to search for other computers within this house. I tried to get onto my daughters (she was with me and consented) but the password thing stopped me. Is it possible that I can demand that he brings those boxes up so that we can set ourown passwords and usernames? Would this stop the access to the other pcs please?
I did send the email from home and I agree that if he is spying he'll be able to see all this.
However, I'm not over worried about that as, seeing as he's the guilty one, I don't feel bad at all for trying to stop him. Next, I'm on the verge of asking him outright anyway. What would really make me feel far more awful is if he's not doing any of this and yet he's under suspicion. But if he's not spying he hopefully won't know anyway. That's the reason I dont confront him with it.
I'm sure he would still help with the tech side of things even if I did prove he was spying - he's decent (this aside!) and would feel bad about it I should imagine. We have a good relationship within the family, he does with everyone, he's just nosey to be frank. He's due to start at Uni in Sept and has chosen one near home so he won't have to live away from us.
However, I would be dismayed if I found out he had been spying and would have to question whether I even wanted him living here at all any more. Like you say the issue of trust is a strong one, I would never consider reading my older childrens txt msgs or msn convo's and the younger ones aren't allowed to use those things anyway.
I like the idea of encryption, do you possibly know how I could obtain something safe that would achieve this? If he asks why I've installed it, then he's spying and I can boldly say, 'Because you're spying on us' and if he isn't then he hopefully won't know anyway.
Once again, thank you so very much for your excellent and helpful reply