@mag, i didn’t have to repair avast. The problem is now solved but through a different method that i am mentioning below.
@igor, thanks for the reply. Avast was scanning every single file on accessing it. The problem was not with Avast, it was the explorer.exe file that was behaving strangely due to some rootkit spyware that recently infected my computer. So I ran the combofix utility which detected the actual malicious program and eliminated it except that during start up, the explorer.exe began executing twice and the “windows explorer” window appeared on the screen after loading of desktop icons completed. So I checked in msconfig startup list but could not find explorer.exe mentioned anywhere so I ran the combofix utility once again and now even that “windows explorer” window has stopped appearing on start up. I guess the problem is solved because Avast is running pretty smooth as it used to run before the infection. :smiley:
Thanks everyone for all your suggestions.:slight_smile: