Misku 0 Newbie Poster

Hello,
first,I'm not really good with computer.
I have a huge problem. For some time now my computer is turning of. Just like this 'pof'. Now it's not related to the power supply (apparently a quiet common problem), because I changed it and it was still turning of after that. After reinstalling windows XP it got better for a while. But then it's starts to turn of more and more.
What I noticed is that it turns of everytime when I do some particular action f.ex. when I want to clean my C drive. But then it would start to turn of whenever without warning. And when it starts to turn of at some point (for example when I play warcraft), it will turn of everytime at the same point even tough it wasn't like this in the beginning. (Am I still clear here?).

I just bought myself Norton Antivirus and firewall 2006 and they don't want to install. The installation starts and then in the middle of it, it goes back and deletes the files he already installed. I get a window with a link to customer service and the link fails to display the page.

Another thing I noticed is that when I browse through my computer some file are written in blue and some still in black. Does it mean the files in blue are not there anymore, or corrupted?

One last thing. My computer is only 2 years old, and should be very good (don't ask me for too much details).

Please help me, thi situation is killing my nerves, and I already lost 12 years of my life getting nervous about it.

Misku