It should turn on and switch to a green band almost iimmediately.
Go to the main screen and check for updates.
Or close it and run the Virtual Technician to see if it finds and corrects any issues: http://mvt.mcafee.com/
Did you make any changes in the PC perhaps a System Restore? Also check if you have any other 3rd party Anti Virus Installed on your PC..!
Thanks. The MVT tool fixed it for now until the next update!!!!!!!!
Glad that you are Okay...!