Hi, everybody!
is there somebody getting the same problem?
I'm in VISTA premium on a ASUS 7A notebook and installed AVAST one month ago : No problem.
Since 2 days now, AVAST installed an update and never succed to reboot.
I'd to remove it to boot. I did 10 times removing other like spybot but nothing
every time now I reisntall AVAST I can't reboot (black screen) even living it during 1 hour. No change.
I'm really off. Any suggestion please.

I got the answer from AVAST forum.
First : desinstall corectly and completely the NORTON free version with the removal NoRTON tool kit (download on their site)
Second : desinstall idem the AVAST version which created the issue.
Third : reboot and reinstall the last version of AVAST.
Somepeople did it and it works.