Resolved Desktop shuts down when trying to open a program and then restarts by itsel

The title says it all.

It started a few weeks ago- my son was playing PC games and out of the blue the computer would go "dead" and then starts again.

Since today, the following happens- I start the PC, enter the password, the screen shows the icons, but when I try to open a programme, the PC goes "dead" only to restart by itself.

I do not have all the details of the system now, but my OS is Windows XP SP2, I have 2 hard drives, 160GB each and I think 1 GB of RAM.

Thanks

 

I downloaded the requested file in my laptop, used Synctoy to get it to the desktop, synchronised, but when I opened my desktop, it immediately shut down. So I cannot run the requested log.
Sorry

 

I took my PC to the guy that usually works on it, so I suppose this thread is closed