Hi thanks for the reply, I have run memtest and there are no faults, I used the following memory
CMZ8GX3M2A1600C9 - 8GB (2x4GB) Corsair Vengeance DDR3 PC3-12800 (1600), Non-ECC Unbuffered, CAS 9-9-9-24, XMP, 1.50V
as recommended by Scan.co.uk, I see loads of people all over the world reporting the same issue in other forums..
Regards..