I am really grateful for your help over the last two weeks.
I've been surfing for approx twelve years and this in the first time I've had a problem like this. I guess I've just been lucky.
Thanks to you and NonSuch I am now back on track and you can be sure I'll be doing all the necessary checks of my system in future!
Having my PC back is the best Xmas present this year!
Have a great Xmas and all the best for 2010.