i have a Sony Viao model vpcf136fm it is a little over a year and a half old. i used it for about a week and it has been on a shelf since then. i tried to start it up and there is no video? the screen is lit, but no video? i hooked it up to my pc monitor and it started up. there was a problem with my network drivers... i uninstalled them and restarted and now it does not start up or show up on external monitor??? please help?