Thanks ady4um for all the suggestion. The BSOD did happen while i was browsing in firefox. Since then i have uninstalled and reinstalled firefox and all the add on as per your suggestion. I also tried to update the video card driver from hp website but it turns out that i already have the latest version and infact hp site has a older version of the driver. Now the pc is behaving normally and no BSOD so far looks like everything is fine now. Don’t know if avast has issued some update or not. Thanks again for your time.
With regards
Gautam