system re-boots spontaneously

Windows XP >> system re-boots spontaneously OK. I've solved most of the problems but a few remain.

Primary: how/why did XP Pro re-boot my computer at the moment I clicked a
file that was on removable media?

Secondary: Why didn't system restore put my system back to what it was
before the problem? (I had to go back and re-establish several important
settings, including re-activating Quick Launch).

Tertiary, and separate: on a single-user computer, why is it necessary to go
to Windows Explorer and enter an Admin. password to be able to change
settings for the Explorer browser?

Windows XP517

Windows XP >> system re-boots spontaneously OK. if your PC is rebooting without reason, then the first
thing you need to do is set Windows so that you get a blue
screen instead out just rebooting your system. Having it go
to the Blue screen will give you the stop error which will
give a better idea what is causing the problem . Now the
reason you can run System Restore and it doesn't fix the
crashing problem is usually a hardware problem but could
stiil be software related. Did you install new hardware
lately? if no then check tomake sure all of your internal
cables are on good and your Cards are seated. If that don't
do it, go to start, run and run msconfig and click the
startup tab and disable all of the programs. restart the PC
and if it fixed it turn the programs you disabled one by
one rebooting after each one you turn back on until you
find the program that is causing the problem the iternet
Explore problem will have to wait for another time I got to
go.
>-----Original Message-----
>OK. I've solved most of the problems but a few remain.
>
>Primary: how/why did XP Pro re-boot my computer at the
moment I clicked a
>file that was on removable media?
>
>Secondary: Why didn't system restore put my system back to
what it was
>before the problem? (I had to go back and re-establish
several important
>settings, including re-activating Quick Launch).
>
>Tertiary, and separate: on a single-user computer, why is
it necessary to go
>to Windows Explorer and enter an Admin. password to be
able to change
>settings for the Explorer browser?
>
>
>.
>