restarting problems

[Philip]

When I boot my pc with Winxp pro, it makes restart by
itseft. I did not install any new devices. Any ideas? if I
reinstall winxp I will loose some files. Is there any way
to get access to folder "My Documents" in order to take my
files?

 

[Miha Pihler]

You can put your HDD into another PC and copy all your files there.

At what stage does restart occurs? Also check hardware before reinstalling.