|Yes, viruses can cause "disconnecting" you from the internet.|
Did you verify that you are actually connected to it ... ?!
Why not simply turning off your router completely including your laptop and any other devices connect to the router, then after 30sec or so ... you 1st turn on the router and wait till the lights come back on, then secondly the laptop and try to re-connect by scanning for your router ...
If that does not work ... you can try and connect the laptop directly to the router via an Ethernet RJ45 cable (if u got one handy) and go into SAFE MODE WITH NETWORKING to try the direct connectivity!!
Let us know