Whjy does my Compaq Presario c700 keep crashing?

I currently own a Compaq Presasario C700 which I mainly use for music. It came pre installed with Windows Vista and i use Itunes as my music program. I have also downloaded and installed Vuze, and on average download approx 1gb of music per month which fits fine on my laptop's hard drive but I also back up with an external hard drive. I initiially used Norton 360 antivirus however I have reecently changed to use Kaspersky 2009. I also run a weekly full virus scan to prevent any problems and 'as and when' quick scans.

The problem I have is that after about 10 minutes of using the laptop, it crashes. All open programs stop running, and I get an annoying single 'beep' when I try and select out of a program. The only way to get out of this (task manager fails to open also) is to switch the system off and then start again. Again, it will start fine but again after nearly exactly 10 minutes it will crash. I am unable to install windows updates in that time, or to run a virus scan.

I have several times backed up my files to an external, and then 'Factory resetted' the computer, ran a virus scan, painstakingly transferred all my files back over and then carried on. The system then works fine for about a week, before reverting back to it's 'crash every ten minutes' routine.

Running system recoveries simply leads to a dead end, and 'a problem that cannot be solved automatically' however, when starting windows normally it's ok for the 10 minutes.

Any ideas?
Regards,

Dale