Hi. I have tried the above fixes (purge logs and files for updates).
I have check the eventlogs for errors and made sure that Windows Update daemon is started and running.
The problem I have started after I upgarded the hard disk to a larger capacity. Windows itself seems to believe it is still genuine and I've checked for other issues and I've not been able to find any.
I have also done "Conprehensive" virus scans and I have also run disk scanning checks.
The machine is a Packard Bell dot-MU with 4Gb RAM running on an Inter x64 processor (Single core Celeron).
The disk was upgraded from a 250Gb Western Digital Scorpio Blue to a brand new 500Gb WD Scorpio Blue.
The partitions were copied sector by sector to the new disk (to keep factory installed software and work) and a new partition was created to use the remainder of the disk for data and media.
The operating system is Windows 7, version 6.1(?!).7601 (Windows 7 Service Pack 1)
I am also running Norton 360 version 4.3.0.5.
Basically, I'm trying to avoid a factory reinstall if I can.