Dawn,
As little information as you’ve provided in your posting, it will be difficult for anyone to offer you much help. What type of PC do you have…as in CPU, O/S, total RAM, etc.? What brand is it and do you know what motherboard it uses? Dell PCs with a certain ASUS motherboard have been known in the past to have problems with Photoshop. At what point during the opening of Photoshop does your system shut down/restart? If it gets as far as the splash screen, try and note what is going on at the time…loading of fonts, filters, etc. Also, did your system ever work with Photoshop and if so, what signficant changes have you made since you last ran Photoshop successfully? Any such information you can provide may be helpful in isolating the problem.
Regards,
Daryl
Have you read this FAQ: Mathias Vejerslev "Computer locks up, shuts down, or reboots while running Photoshop" 6/5/03 3:49pm </cgi-bin/webx?13/1> ?
You might be using a faulty ASUS motherboard.
Mathias