rebooting pc

[Doc]

hi all

my daughter has a pc that she uses to watch her music videos on (barbie girl etc well shes only 18 months ). i usually switch the pc on for her..and then put the videos on. Nothing has been installed on the pc and the pc has no internet connection. About a week ago the pc started to reboot itself. IF a video is playing it randomly reboots or if in word it reboots. Basically it reboots itself once youve logged on.
any help or suggestions would be appreciatted
thanks in advanced
Doc

[Mickha]

Usually this is a sign that the PSU (Power Supply Unit) is failing, but there are many other things it could be.
First thing to do is boot up in Safe Mode, usually by pressing the F8 key on boot up, but it depends how old your computer is and the BIOS.
Leave it running for a while in Safe Mode, and if it stays on then the problem could be a driver, quite often the Graphics Card driver so try re-installing that.
If it reboots then it could be the PSU, failing memory, Motherboard, Hard Drive, Graphics Card etc, which can only be diagnosed by trial and error.
There are some diagnostic tools available, free, that can test your computer, like memtest, but I usually start with the PSU, although the last computer I tested that was re-booting was down to loose connections holding the Graphics Card in place and it was coming loose and causing a short.

[fabkat]

could also be a sign of overheating..dust gets everywhere and could be clogging the cpu heatsink causing it to overheat and reboot...