Windows not booting up after avast boot time scan!!!!!!

Hi all,

I just finished a full virus system scan. And after that it shows me that a boot time scan is recommended. So i decided to do it and i left my pc on for the night. And now my computer does not want to boot up at all! All i have is a blank screen when powered on, not even my mouse and keyboard light up.

Please help!

More information is needed.

Are you hearing any beep(s) when trying to boot ?
Can you enter the bios/EUFI setup ?
Can you see that Windows is loading and than get a black screen ?
etc.