Thanks for your suggestion. After trying this and everything else and speaking to an Apple tech who could offer no solution either I reinstalled my OS system, I had to do a full erase as the overwrite option would not work. It worked! The system profiler now shows that the graphic card is fully compliant and after updating all the software to the versions I had before it all runs perfect.
Obviously there must have been a bug in the OS but no body it seems knows any other method of correcting the problem.