Thanks for the help. Interestingly I had rebooted and shutdown a few down without it helping the situation. I restarted again holding down shift key, selecting troubleshoot-advanced options-startup settings-restart. The laptop restarted and asked for my bitlocker key, which i was about to lookup and the laptop suddenly powered off. I thought I ran out of battery so I plugged it in, hit the power button, logged in and BAM, Avast flashed its update successful window and I verified the install completed.