Never found the root of the problem. It all went wrong when I attempted to install SP3, so I performed a system restore to the day before I attempted the SP3 install, and all is working fine now.
Not an ideal fix I know, I'd have liked to have found out what the cause was and fixed that, but its working for now which is the main thing
Not an ideal fix I know, I'd have liked to have found out what the cause was and fixed that, but its working for now which is the main thing