Really weird acting...

Ive got a problem with my windows 7 computer. Ive had it for about six months now and its working OK. Although now all of the sudden it started like... Acting weird... I was able to click on some places but i couldnt exit my web browser, neither change to another tab as it deleted the one i selected. Its not a virus, ive scanned the computer lots of times after viruses and ive found nothing. It happens all of the sudden, so i press Alt, ctrl, delete and opens the task manager and then it all of the sudden works, for about 20 secs, then it starts again. I find this very annoying, and would be really happy if someone could help me! Tell me if you need some more information.

Cmon! Nobody knows? This is starting to get extremely annoying

If it is a recent problem, then you could try doing a system restore.

If you need help doing this, just let me know :)

I think we're gonna need a bit more information.

What web browser are you using? (Is it only one causing the problem?)

What virus scanner are you using?

Also.. If you could fill out some more of your hardware specs so we know what you're working with.

Thank you guys!

Tom, i have no idea how to do it but what will system restore do?

Electrotune, Im using Google Chrome, but thats not the problem. Ive tried using the computer without internet on, same problem.

Im using Norton.

Whs, how do I disable all start up programs?

I had the same problem for a while ago, and right before that happened I didnt install anything.
But now, one week later, ive got it again, and its a lot worse. Ive also realized that if I leave the computer for about two hours, I can use the computer maybe 15 mins without any problems. Also, sometimes the sign appears when you click the scroll without me doing anything. Ive tried with another mouse and that problem stopped, but its still acting same as weird as before... Anything else you would like to know?
Ideas?

Thanks!

Yes, i followed that article, but then after I restarted it, it didnt work so i scrolled down to the part if it didnt work. And it says click the services tab or click the general tab, but where is the services or general tab?

I think ive found the problem. And the problem was the mouse! I tried unplugging the mouse and restarting the computer. And then... It worked! Im sooo happy!

Thank you for all the help!