You got a new virus named "korgo" .
When you get the message click Start -> Run and type shutdown -a and press ok.
This will make the shutdown screen dissapear.
Learn more about the virus here:
http://securityresponse.symantec.com/avcen...32.korgo.f.html and removal tool here:
http://securityresponse.symantec.com/avcen...moval.tool.html