I am responding after sometime just to be sure that blue screens have truly disappeared.
Now, I can confirm that they have disappeared.
Thank you for pointing me to NEOFLTR.sys which belongs to Neoteris VPN software.
I found out that this had to do with Juniper which I deinstalled. This was an old software I had
but since I installed new CISCO vpn software it seems to have conflicted with it and was causing the
blue screen. I deinstalled all latest software programmes along with Juniper and tested my laptop for a week.
Then I installed the CISCO VPN again and Now its a month ago and absolutelly no blue screen has ever occured.
So, I wish to thank "softwaremaniac" for his precious help and efforts and I am donating now to you.