The message should be "Your Windows is infected with annoying trojan", but heck, you don't really expect honesty from those folks?
==Download this file to your desktop: http://download.bleepingcomputer.com/sUBs/ComboFix.exe
- to run it dclick combofix.exe and follow the prompts to start it. When finished, it will produce a log, C:\Combofix.txt - post that log in your next reply.
A word of caution - do not touch your mouse/keyboard until the scan has completed. The scan will temporarily disable your desktop, and if interrupted may leave your desktop disabled. If this occurs reboot to restore the desktop.
We can fix this without a reinstallation.