Limited Internet Connection/Windows 8.1/Atheros AR9485

My computer was purchased a month ago, and the connection has been working flawlessly up until yesterday. It shows that I have a limited connection. I have an HP desktop with internal wireless (Atheros AR9485), running Windows 8.1. The router, a Netgear WNR3500v2, is located on another level of the house, but all other wireless devices in the house work fine, which include my laptop that I am currently using right next to my desktop. I have updated the firmware on the router and the driver for the AR9485 and I still have a limited connection. The settings on the router were not messed with at all, so I am at a loss as to why this randomly became an issue. Any help would be greatly appreciated.

 

And neither the desktop or WAP (wireless access point - often integrated with the router)have not moved since it initially worked? This includes WAP antenna orientation? No new microwave ovens or other electronic devices placed nearby?

Have you run new power or other cables near the back of the PC since then?

I really don't like internal wireless devices - especially on PCs. For one, PCs tend to sit low on the floor - not the best for radio reception. Also, PC cases tend to be metal. Putting a radio inside a metal cage is never good for radio propagation. So I much prefer, for PCs, wireless cards with external antennas like these.

Have you scanned for malware?

 

Yes, nothing was touched prior to this issue. It has turned into an issue with just my wireless to all wireless devices, so it has to have something to do with the router, modem, and/or something on Comcast's end. I scanned for malware and it found quite a bit, but it didn't fix the issue. I am really at a loss to what this could be.

 

Wait! You say just wireless devices - if you can connect via Ethernet (wired) and you can access the Internet fine, then the router, modem and Comcast all work.

And now we assume it is not limited to this new HP, right?