No I am not offering free phone calls, although it appears that this is what someone got from me without my knowledge.

About a week ago I noticed that I was unable to make any international calls from my home phone. After contacting the telecom company here in Italy I was passed on to their fraud department who said that someone was using my computer to make premium rate calls. As this was not consistent with my regular phone usage it was flagged up and the phone company took action.

Apparently my computer was somhow infected with a file which allows a remote user to make phone calls without my knowledge provided the computer is turned on (it doesn't even have to be connected to the internet ). To cut a long story short I have wiped my hard drive clean, reinstalled everything and now have to use a PIN to access my phone line.

I am very careful about the sites I visit and the emails I open, but somehow I was still infected. What I would like to know is if anyone can tell me how this actually works and what other details they may have got from my computer?

Thanks