The white screen sounds like the video card is no longer outputing a signal.
To troubleshoot the reboot, this is probably a secondary effect of the
system crashing, and the fact that you have automatically restart set. So
stop that first.
control panel/system/advanced/startup and recovery settings
Untick automatically restart.
When it happens again, you should get the famous blue screen. Post the
information you see there, i.e. The name of the stop code, all the numbers
that start 0x.. and if there is one, the name of the driver causing the
problem (a filename with a .sys extension).
In the meantime have a look in the systsem event log,
start/run
eventvwr.msc
Click on system in the left pane.
Look for any events in the right pane flagged with a white cross on a red
circular background and labelled "System Error" or "Save Dump".
Double click on the latest of these, and use the copy button to copy the
error into the clipboard, and then paste it into a reply. The error logged
doesn't contain the name of the driver, we'll have to wait until it crashed
for that.
Paul
