Every time I open any web page I get "preparing to install" popup

[GeesNutz]

Any webpage I open, a window appears for a second, telling me "preparing to install". It doesn't seem to be a problem, but this never happened in the past.
I'm using internet explorer, and windows 7. I'm wondering why this is happening now, and how I can make it stop. Any information greatly appreciated.

[Dairyman]

You're probably infected with a virus.

Read through this and post the logs in the 'Computer Viruses and Spyware' board.

Did you install any programs recently or follow any unknown links (particularly from MSN/Windows Live Messenger)?

Good luck.

- Dairyman