Okay, I don't want to count my chickens before they've hatched but, I think I might have cured the problem or rather my brother has.
He did a search on the TDL3 root kit and found a link to Kaspersky who have a TDSSKiller, what ever that is. I have run this and it removed 3 reported problems. I was a little worried as the instructions said I wouldn't have to reboot, but the program asked me to do so. Well I did and all seems okay so far.
Firefox is running okay, so too is Opera which I installed to see if I could get round the virus. No pages have opened up on their own and searches in Google are behaving normally now. My network is now stable and I have not experinced any further spurious Network activity.
If anyone needs the link, give me a shout and I 'll dig it out.
So far so good and with no reboot, system restore or incompatible MAC.
Just kidding, thanks for all the help, I hope I haven't tempted fate.