after I click update button on the AVAST window, my PC went to a dead mode.
I shut down and restart it but cannot go to the boot menu, all is black. Suspect the BIOS is damaged, what to do?
hey and welcome to the forum. are you able to boot into windows? if so try a clean installation of avast and see if that could help.
run the uninstall tool for avast and reboot your system. install a fresh copy of the latest version of avast
http://www.avast.com/uninstall-utility - uninstall tool
http://www.avast.com/free-antivirus-download latest avast build.
good luck and lets us know on the process’s or if you need further support
Have the same problem but cannot even get into boot mode. Keyboard does not react either…please someone help
same problem here … 
think I will reinstall … can’t wait so long