Nigel
Your uploads proved interesting.
Select Start, All Programs, Windows Update, Change Settings. Under Important Updates is a box showing the current setting. Click on the Arrow down to the right and change the selection to “Check for Updates but let me choose whether to download and install them” and click on OK. Restart your computer three times to clear pending updates.
I suggest you run the Microsoft Genuine Advantage Diagnostics Tool in normal mode and copy and paste the results in a reply for further analysis:
http://go.microsoft.com/fwlink/?linkid=52012
Run the Tool and when it completes click the Copy button, open a text file like Word or Notepad and select Edit, Paste. You can paste directly into a reply here. Open a reply, right click and select Paste.