Thanks for your reply, but I am unable to do anything after this screen appears. I have tried turning on the laptop after switching off my router, but still same screen appearing.

Yes but still if its their property,then why I was able to use it for last 9 months?this issue should appear in start

dencal I am unable to do anything after this screen, please elavorate, do you mean that I am having issue in my network router?

sml156 ,Bat 1 If you are saying its re-furbished or stolen then I...

I have deleted the partitions and re-installed, But I cant do any thing after that screen,how can I open task manager?
If its a stolen PC,how I was able to used it for 8 months?

I have purchased it from store and I have sales reciept of it too

I was checking emails, and I didnt clicked any link,neither I installed any add-on, I suddenly got alert to restart the pc to disable user accounts and it get restart automatically.
When it...