HI,
Right click on My Computer and select Properties from the drop down list.
On the open window click on Advanced and click on System Startup Button,
under the Header System Failure;
[ ] Automatically restart uncheck this option
Click Apply then OK and restart your computer and capture any error messages
comes up and post it back here, check for any error messages in the Event
viewer and send them here.
HTH
Regards,
nass