Can't start Windows, very strange problem

Hey guys, I'm working on a Toshiba Satellite A100 with a very strange problem. It seems like as soon as the computer tries to load the Windows kernel it crashes the laptop. The laptop gets through POST fine but as soon as it tries to load Windows it just sits there, no HD activity, can't turn caps lock on/off or restart via CTRL ALT DEL, it's completely frozen. I'm able to get an F8 in there to try safeboot etc but as soon as I hit enter for any of the other options same thing happens.

I popped in a Windows install CD to try to repair the Windows installation, it gets through the first 3 minutes of "loading files" fine but as soon as it tries to display the initial options with the "starting Windows" status it freezes. I booted off a UBDC and tried to boot into FreeDos and same thing happens. The HD is fine, I've swapped it out into another laptop and Windows starts up perfectly. Also, when I boot off the Windows install CD with a different HD in it does the same thing.

I booted off an Ubuntu CD and it works perfectly, I even managed to hook up the HD externally to my other laptop, shrink the Windows partition, then install Ubuntu onto the drive and it worked perfectly. It's so weird, it's like as soon as it tries to boot Windows it locks up. I've never seen this and am thoroughly confused.

Any ideas????

Already checked memory, cpu and any other test I could run, everything seems fine. I'm TRYING to re-install Windows, that's the problem. I'm trying to format the whole drive and re-install but it crashes during re-install too.

I tried a different Windows disk, same thing. I don't think it's the drive itself because I was able to install Ubuntu and it always crashes at the same point when it tries to launch the Windows kernel.