I have a problem with a laptop Hard Drive that I cannot work out.
The laptop belongs to a friend who accidentally unplugged it (no battery installed) without shutting it down. The Operating System is Vista Home Premium.
Now I cannot get it to boot. All I get is a black screen with a flashing cursor. I thought the MBR was probably corrupt, but cannot fix it. I cannot get the safe mode options up when I press F8, and it refuses to boot from the CD/DVD drive at all.
Now comes the strange part.
I took the Hard Drive out and took the HD out of my laptop and swapped them (my HD in friends laptop abd hers in mine).
My laptop started up ok and I was able to access her files etc, but obviously drivers were different etc.
My friends laptop with my HD in it started ok as well. 
But when I put the original HD back in friends laptop I again cannot boot and get the Black screen etc again.
This has got me very puzzled.
Does anyone have any ideas about this?
Thanks.