I *think* I have solved the problem
I am pretty sure my mouse is dying. Not sure why it produced those symptoms but as soon as I plugged in my laptop mouse, the problem went away
Or at least it seems to have gone away.
Thanks for answering my thread you guys
Orpheous, you are always coming to my rescue - I think you had better start billing me
Edit: Yup, definitely the mouse. I just plugged it back in and the problem came back... took it out again and problem went away. Geez, I am better at diagnosing faulty devices than the guys who sold me the faulty graphics card
It is probably from my child continually grabbing the mouse, walking it around the house and bashing it against various things. Might not get a wireless as the next one