Right folks, I've got an update to my saga.....
I RMA'd the card last week and after 'extensive testing' the card was deemed to be fault free so it was returned to me.
I removed the driver with DDU before installing the card then reinstalled the driver from the disk.
I started it scrypt mining and it run faultlessly for 24 hours (both my previous cards ran faultlessly until the first time they were shutdown - so with this in mind, I've just shut it down for the first time)
1st problem, the PC didn't shut down, it just went to a black screen and hung there. I killed it with the plug and restarted it again.
The PC booted up fine, I clicked on MSI Afterburner and the screen went black again straight away. Killed it with plug and started again.
Once more, it booted up fine. Started Cgminer and once again, black screen. Killed it with plug again.
Restarted the PC, booted up fine, tried cgminer again and this time it's working. If it didn't work this time, I was going to boot into safe mode and remove then reinstall the drivers from the disk again.
Has anybody any idea what is going on? Ideas what to do next?
C