I have a laptop that will occasionally boot, but not often. Usually it locks shortly after starting the boot process. It does have diagnostics in it (in the cmos setup) which say the hard disk and memory are both ok. I've run the test multiple times without problem. However, almost all attempts to boot to the o/s on the hard disk (windows vista) result in a blank screen. the vista logo, load screen etc are never shown. I can't get a boot menu to let me choose to boot to safe mode. I tried various live disks, all of which result in the same thing. I tried booting to spin-rite (runs on free dos). spin rite locks most of the time, but once and a while I can actually get the software to come up .. .as soon as it starts to run the diagnostic, the computer locks hard. I've never been able to successfully run the software.
anyway, the bios setup software is the only thing that will actually run on the machine. anyone have an idea of what may be wrong? i would guess hard disk or memory, except those are the two tests I can actually run ... and both succeed every time.