UGH! Hands OFF ffs!!

I am currently spending the night at a friends house, I've been here a week and a half right now. Of course, I brought my beloved maya, my laptop, with me.

My friend borrows it from time to time, and I'm okay with that.

The only thing I'm NOT okay with though, is when he does things with it tbefore asking me.

Example 1;

He is on my computer, and installs a cleaning programme, WITHOUT MY KNOWLAGE!
It would've been okay, if not for the fact that every single one of my saved passwords got deleated!
I mean, seriously! It pissed me off when I got 'home'!

Example 2;

Again, he's on my computer while I'm at school. And when I get it back, he's changed the colors on the windows.

I know neither is really a big deal, but the thing is that 1; he himself is very easily ticked off if you mess with HIS computer without asking and 2; my computer is MY computer. If you wanna install something, then freaking ASK!
Besides, my computer is sort of sacred to me. It's one of the few things that I have in life that is keeping me at a somewhat sane level.

I know, I know, I got to stay here and eat here and everything while I'm here, but it just annoys me when people do stuff to my computer without asking!

I wouldn't be this ticked off if he just would've ASKED first. I mean, it's not that hard to send a text to ask 'is it okay if I download this to your computer' or 'can i change the colors?' or something, is it?
It's not too much to ask for either, right?
I mean, if this was your computer, how would you react if I came and downloaded somethin, or changed somthing on your computer without asking first?
Isn't it good manors to ask before you do somethin to someone elses stuff?

I don't know, maybe I'm the one who's wrong here..?

Sorry for the random rant, just needed to vent..