I have got a Sony Vaio PCG-F305 laptop which seems to be having a very strange problem. It will boot into windows fine, but as soon as the drivers and all of the start-up programs have run it seems to switch off, but leaves the power light on. It is as though it has gone into hibernation, but there is no way to revive it. I have tried installing several operating systems on it, including XP and 95, but nothing works. Strangely, it will work fine in Safe mode or in DOS, but will refuse to even install Linux. I have tried changing the power management in the BIOS and changing the BIOS battery.
This seems to happen whether the power is coming from a battery or from the AC supply.
Please can someone help, as I have asked everyone I know, and they are all stumped.

Thanks

Jon