THE LLVM is almost entirely due to wrong driver version / files. It was my problem and many other peoples from the previous pages (I went through them all...)
To begin with, just check by trying:
oclvanitygen -D 0:0 -k -o found.txt 111111
and
oclvanitygen -D 0:1 -k -o found.txt 111111
If it fails, uninstall the ATi/AMD driver, then show hidden devices in device manager and if any hidden display devices are revealed, delete them. Then download and run Atiman Uninstaller to remove any leftovers.
Then reinstall 12.8 driver which most people find works.
http://www.filehippo.com/download_ati_catalyst_vista_64/13064/ which is for vista, W7 and possibly W8 64-bit.
What "hidden devices" might there be? Also, how would you recommend removing in the first place? What I have been doing is downloading the installer for the version that I'm running, and using the uninstall option from that as Windows doesn't list it as an option in Add/Remove programs, but this seems like an odd way of doing it.
As for the Atiman Uninstaller, it needs to have UAC disabled to install it, which seems a little odd, and it's very large for an uninstaller... Is this generally accepted to be an OK utility?
They are devices that windows knows existed at some point in time but are not presently in the system or at least in the same configuration it has been previously. They can accumulate especially if you are swapping card types around and moving PCI slot positions. In Atiman Uninstaller it refers to them as 'ghosts' in the first texts the program displays, although, I have found it will remove them anyway, I guess its best to follow their advice and do it manually. They can also accumulate during driver changes if you use the regular AMD install/uninstaller.
I have it in my list of installed programs as "AMD Catalyst Install Manager".
Atiman Uninstaller uses a huge range of scripts and operations to remove all kinds of different things. No doubt you will be impressed/amused at how much stuff it does. It is VERY different from any uninstallation you might've seen for a normal program...
Yes, you were not wrong, I was both impressed and amused!
Sadly, however, it still doesn't work. I've rewound to 12.8, rebooting at all the times I was supposed to, and I still get the same error
Many thanks for all you help and guidance, I think I'm going to give up for now and come back to in a month or so, once I can actually afford the time to play with things like this!
PS I was about to write back to R_Tage_11 to say a) it was free so calm down and be a bit more grateful, and b) try a dual boot if you can't settle for older drivers, i.e. exactly what you said, but you beat me to it!