How to solve Avast freezing computer problem?

I was working on my computer when all of sudden it stopped working. Ctrl+Alt+Del won’t help. Power off button won’t do anything. At last I had to switch off the power supply to restart it. Again after few minutes of working same thing happened and in a span of 2 hours I had to restart my computer for more than 15 times. I was going crazy as I had replaced my hard disk few weeks back and switching off power too frequently could cause damage to it.

My first doubt went on some virus which might have sneaked in my system, though I am using Avast home edition since long and never had any problem. I started scanning my computer and it froze again. I restarted the system again and thought of updating Avast first. I know, it updates itself automatically but sometimes I go fanatic. Run of “Update engine and virus definitions” went fine. I thought of running “Update Program” too. As soon as I select this option computer froze again. My doubt on some smart Trojan / Malware / Virus was getting stronger. But when after 5 reboots and attempt to run “Update program” went fruitless, I uninstalled and reinstalled Avast. No use, still same problem. I googled and came to know about Avast clean uninstall utility. I went through the instructions given on the utility page at avast website, downloaded, uninstalled avast using this utility and then did a fresh installation of Avast.

After this all the updates went just fine and it has been four hours continuous work without any reboot :).