A big thankyou to all who took the time to help me, after a tough week this is the first chance I've had to look at it again.
nmb
Did the uninstall/reinstall process and so far so good, avast is currently up and running and all is well.
DavidR
I thought long and hard about the hijack program but decided to try the above first as it seemed the safer option to me.
Thanks again
scoop