AVAST = BLACK SCREEN WITH CURSOR/BLUE SCREEN

[Unlucky]

Hi, i have installed AVAST on my laptop and straight away after the first reboot i got a black screen with my cursor and i can't do anything apart from going to CTRL > ALT > DLT menu which wont do anything. And everytime i try to go into safe mode a blue screen pops up i can't do anything! Please help!  I've got the RUFUS software which might help but what do i do next? Can anyone give me any fixes for the rufus software USB thing?
Thanks

[marc-d-l]

What OS are you using ? what AV did you have before you installed Avast.How did you remove the old AV?
What else where you using for security ?
Do you have a repair disk ?