Okay, thank-you once again for all your help.Download Windows Repair (all in one) from this site
Install the program then run it.

Go to Step 2 and allow it to run CheckDisk by clicking on Do It button:



Once that is DONE then go to Step 3 and allow it to run System File Check by clicking on Do It button:



Go to Step 4 and under "System Restore" click on Create button:



Go to Start Repairs tab and click Start button.



Please ensure that ONLY items SEEN in the image below are ticked as indicated (they're all CHECKED by default):



Click on box next to the Restart System when FINISHED. Then click on Start.Thanks for the new suggestion.

Unfortunately, I was unable to run the program. I first tried with the installer version. It installed with no errors, but then, on launching the application, a message box appeared with message 'Unexpected error'. I then tried the portable version, but the same error occurred on launching the tool. Perhaps it is reliant on a damaged windows DLL? I will schedule another check disk now, via the normal windows interface.Sorry for the delay. I'm going to try one more thing and if it doesn't work I will move this topic to The Windows 7 forum.
Please go to this site and it will instruct you how to run the Action center. It's suppose to fix a lot of problems.