No Internet Access: Wifi or Wired

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Ultimate, Service Pack 1, 32 bit
Processor: Intel(R) Core(TM) i5-2430M CPU @ 2.40GHz, x64 Family 6 Model 42 Stepping 7
Processor Count: 4
RAM: 3112 Mb
Graphics Card: Intel(R) HD Graphics Family, 1364 Mb
Hard Drives: C: Total - 56924 MB, Free - 13915 MB; E: Total - 652257 MB, Free - 59114 MB;
Motherboard: LENOVO, KL6
Antivirus: Microsoft Security Essentials, Updated and Enabled

I cannot connect to the internet via my router either by wifi or ethernet cable.

It was all working fine until a couple of hours ago.

I can get online by using my phone as a hotspot and connected to the laptop via the USB cable. The phone is connected to the router via WIFI and works find. So do other laptops on the same router.

When I do I diagonse problem in Windows I get "the DNS server isn't responding" message.

I've tried doing an ipconfig /flushdns
ipconfig /registerdnd to no avail.

Any ideas?

Thanks.