Due to a virus I had to reinstall windows and then all my drivers. My key board is now driving me nuts! The " key should be the @ key and the # sign should be the sign for the UK currency, (God knows where that's disappeared to!)
Any help would be much appreciated. I've reinstalled the software twice and specified UK settings, but to no avail.

Check ALL (there's about 4) of the setting in Regional Setting in the Control Panel.
Basically you have the keyboard mapped as USA rather than UK.