Victorio,
Follow only the steps here;
READ ME Before Posting A Request For Assistance!
Ending up with the HiJackThis scan. Post that log and the log from the AVG Anti-spy here.
As far as getting back the Yahoo accounts I will have to do some searching to find out who to contact in the UK as the telephone numbers given on the link I gave you are in the US. Do the required scans first and I will continue to search for you.
Judy