Can anyone help? I have a dell dimension 1501 laptop which boots fine, but within about four or five minutes a blue rectangle appears in the centre of the screen with rows of small vertical white lines covering the screen. It then shuts down and restarts. I cannot keep the machine open long enough to virus scan, remove files I need to save, or change any settings through Control panel. I have been reading a great deal about this type of problem, and have run the system and hardware diagnostics, which ran fine. Problem not related to power supply or over-heating. I have two batteries for the machine, both of which are holding good charge. At the time it first happened on Sunday, I got a flashed message of "Threat Discovered" in my AVG software. It offered me the choice to heal, which I accepted. It began immediately after selecting "Heal". Starting in Safe Mode the problem happens just the same. I have de-selected the "Automatic shotdown at system failure" in the system settings. MAkes no difference. I have so many work files on the machinr that a clean re-install is not an option at the moment.

See event log files if you can. Get a live cd like knoppix to move your files off to a usb flash or networked drive. "Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10