Internet Connection Not Working??

I have an HP Entertainment PC, and recently it has stopped connecting to the internet.
I downloaded a proxy server, (UltraSurf), in order to bypass a firewall.
The computer worked fine for the one day that I used it with the proxy, and then the next day it would not connect to the internet. I ran diagnostics from every angle and the solutions were not working at all.
My Norton360 also expired a few days before I downloaded ultrasurf, however I have run a full system scan with Windows Malicious Software Removal Tool, AND Windows Defender.
Nothing was detected.
There is otherwise nothing wrong with my machine, it runs fine, full speed, but offline.
I also had a day where I tried the internet and blank internet popups came up. (I believe the URL said something like "Reaching DNS" or something.)
As fast as I could delete them, they kept coming back up.
I restarted the system, and it did it again.
And then the NEXT day, nothing. There were no popups, just "Could not connect" Run Diagnostics, type message.
I have had Spyware before, I know the symptoms fairly well, there are no strange popups, no slowed system, and no new toolbars.
I have only downloaded UltraSurf recently and I dont believe that is the cause of this problem.
All of my other laptops connect fine, and for two different connections, It must be a system error.

All suggestions and feedback are greatly appreciated.

Thanks!!