Windows 7 Home Premium won't update

I have a laptop which gave some SMART warnings because the disc was on its last legs. Before it failed completely I managed to create a set of recovery discs (which unfortunately weren't made when the laptop was first purchased). I have replaced the HDD and restored from recovery and the system looks fine except that Windows Update won't work. It has a Red Crossed Shield and when I click on "Check for Updates" it says "Windows Update cannot currently check for updates, because the service is not running. You may need to restart your computer". I have restarted and confirmed that the services are running but still it won't update. I have done much surfing on the Internet looking for solutions and have tried many things but still can't get it to work.
Any suggestions would be much appreciated.