Sounds like hottext or toptext or something similar.

For starters do:

1. start -> settings -> control panel -> add/remove programs
2. select TopText (or similar name)
3. select uninstall and follow any directions you get
4. reboot

Then install something like Spybot which will remove various malware from your PC.

yipee,

nasty links gone.
many thanks

Unfortunately everyone these days needs to be concerned about protecting their computer -- there's too much malware around.

Defense in depth is important, and there are simple, effective and free options around; I'd certainly suggest that anyone had:

anti-virus -- AVG or Norton
firewall -- Zonealarm or Sygate
spyware killer -- Spybot and/or AdAware

Installing AVG, Zonealarm and Spybot will give you simple, effective and free protection against most of the threats on the internet.

And going a little further (replacing AVG with Norton anti-virus, running AdAware in addition to SpyBot, replacing Internet Explorer with Mozilla and disabling javascript and automatic previewing in your email client) will make things even safer.

It's also worth checking how secure your computer appears using sites such as Shields Up, Scanit and Qualsys.