Strange Messages in Yahoo Messanger while chatting?

I stay in Japan, and my PC has all the necessary protection - firewall, anti virus etc.

My daughter is in India, and uses a public PC - it is one in her hostel - however she has installed the AVG etc.

For last 3 week, when ever we chat - typing - strange messages and links to sites keep coming to my side of the messenger. They are like - "why not see the beautiful girls on http://picxxs.com ... ".

I tried Trillion - where I connected to 2 of my yahoo accounts at the same time - and it stills comes in every 20 secs - to both the accounts. This ONLY happens with that one PC - as when my daughter is chatting from other PC - it is normal.

Any views - why?

If this is a virus, what are the possible remedies?

Thanks in advance for assistance.

Strange Messages in Yahoo Messanger while chatting?norton 360

I'm not sure...sorry!