Someone is tampering my pc

[mit_24]

Hello,
sir i have taken internet connection through my mobile ..I get a critical error saying there is a problem with my internet connection.

Someone has tampered with your computer
and i m not able to open any site.what should I do to get rid of this problem..

 

[JBB-SaDo]

On your router: Does it have a light by the internet? showing that you are connected?