I get the same problem nearly every time i log on to the internet.
At one stage i was being hit at least once every 20 to 30 mins with Trojan hack viruses. Now it's probably only once or twice every few hours.
It seems to be mostly the same person/company/whoever thats doing it. I was kinda late installing a firewall onto my computer, this was probably half the problem.
It can be a major pain in the butt, and very frustrating.
I'd advise getting the Norton Personal Firewall, it tracks thier IP addresses and gives the location and network they are using.
Although when i reported all this information to the network of this persistant pr**k, i was told that it was not illegal unless he had actually gottin into my computer. In which case i would have had no idea that he was there.
I forget the URL, put there is a Trojan remover program that you can get for free on the internet somewhere, i think it is actually called 'Trojan Remover'. Try Google.
Also try 'add-aware', another free program for removing spyware. Sometimes these can set your firewall off.
Beware of dowloads you get from Shareware programs such as Kazzalite etc, these can be used by so called 'hackers' to by-pass your firewall and install Trojans.
PS. If i you ever meet someone you tells you he is a 'Hacker' (Cyperpest). Kick him hard in the nuts.