Hi I think i have managed to clear the problem this evening on my friends pc.
Not sure what was the actual cure but this is what i did :-
If you remember he was getting a warning of A TROJAN named Hider each time he booted up, Avg would not update or run a scan, and internet explorer would open 50% of sites seached. .
So :-
1. I uninstalled Avg.
2. I restored system to a point 14 days earlier using the restore option.
3. The pc then allowed me to download Chrome , free version of Avast, and free version of Malwarebytes.
Immediately all web pages became available in Chrome.
A full scan of MalwareBytes found and trapped two Trojans.
A quick scan of Avast found two more trojans of very low threat.
Friend is going to do another full scan on Avast tomorrow.
So at the moment his pc is running faster and looks reasonably clean.
By no means am i a teckie , i am guessing the problem lurked in Internet EXplorer ( i may be wrong).
The combination of the above hopefully has improved matters considerably.
Friend says he looks forward to running scans on a regular basis.
If he gets any problems in the future i will certainly return to this forum.
Just one question now remains......... he likes Chrome , he uses Google for his search engine........... Would it make sense to un-install Internet Explorer, or should i leave it sitting on his pc ?
Regards
Kep