0x0000007E 0xC0000005 0xBAB51184 0xF78EDD44 0xF78EDA40

I am now getting this BSOD every time I try to start-up.
It occurs a little after the Windows XP black display with the
progress 'train'

I have changed very little before the error appeared and I think all I
had done was update and run antivirus, antispyware, Windows
'housekeeping' programs that I have run many times before.

I have had BSOD problems with a DVD drive but this is now
disconnected, as are all USB devices.

As I cannot start the PC either in Safe Mode I cannot get access to
anything to change!
Tho' the BSOD from Safe Mode results in 0x0000000A 0xF79B0354
0x000000FF 0x00000001 0x804E5619

I have tried restoring to 'previous working configuration' 3 times but
still no change in the BSOD.

This is Windows XP Pro SP2

Any help would be much appreciated

Thanks

Nigel