Thanks. I have tried your suggestions.
Suggestion 1: I get to the Windows Error recovery screen and I am given the option to launch startup repair or start normally. Both options result in the same BSOD.
Suggestion 2: Booting from OEM supplied OS recovery DVD and from the Windows repair disc that I created when first setting up the machine - both fail with same BSOD. (I have no actual installation disc as not supplied).
The full error code is:
STOP: 0x00000034 (0x0000000000000107, 0xFFFFFFFFC0000420, 0x0000000000000000,0x0000000000000000).
I have attached pictures of the BSOD screen and the two screens from which I can run recovery / repairs.
Any further thoughts / ideas would be appreciated.