Kempus,
I am sure Ifalconer is right.
In the last few days I have noticed a massive increase in hacker activity. It is entirely likely that for some reason, more people out there than usual are sending out nasties of every description to b****r up our systems.
I have both a firewall and anti-virus software, (the latter is updated on line every week and sometimes more often).
May I suggest you follow suit. It doesn't cost a fortune and it has saved me many times.
Very best regards from the pilot with the cat and a pointy hat,