Screen goes black 10 sec. after Windows loads.

Win Vista Home Premium. OK, I power on the and everything starts out fine. I see the Toshiba splash screen, the green Windows scrolling bar. OS loads can see desktop then I have 10 sec. till the screen goes black. The power light is still on but no HD activity light at all. I can boot into Safe Mode and works fine, can stay on for hours if I like. But will not find my network, direct wired or wireless, keeps assigning 169.xxx.x.xxx address. Thought it to be spyware or virus related, but could not get online in safe mode or even onto my local network. Ran the Toshiba restore disks. Now as Windows starts for first time it goes to a Toshiba splash screen to finish setup saying it will reboot after it finishes. This happens about 10 sec. after Windows starts at which time the screen again goes black. Still have the power light lit, but no HD activity light. I let it sit like this for hours and no change. Now if I boot into safe mode it says Windows installation is not complete to click OK to restart in Normal Mode to finish installation. No matter if I cancel the final installation step in Normal mode or not, 10 sec. after Windows loads the screen goes black.... PLEASE HELP!!!