Dim 8400-Registry_error

The problem- 8400 is the system

registry_error      tech. info- STOP 0X00000051 (0X00000003, 0X00000003, 0X00000000,0XE120C000

When I go to system restore- brings up the blue screen above

When I try to install a new installation of windows it goes thru the first motions then blue screen again.  or a screen that says "setup didn't find any hard disk drives installed on your computer. 

I can't get to the safe mode

I try to hit f12 and get keyboard failure

I can't get to a prompt to be able to access the cd's contents

I have run all the diagnostic tests that are avail for hard drive/blue screen/and all the tests passed.

I have tried everything that I can think of....help!!!!