Unable to coect to WiFi via Win7 Desktop's internal or external USB Wireless NIC (can ping; no browser access); can use Android USB tethering

I have had this issue since I moved into my new sublease a few months ago. Effectively, I am unable to coect to my apartment's Comcast WiFi using my Windows 7 desktop's built in wireless card. I can see the SSID, the password authenticates, pinging sites like google.com or superuser.com works as does nslookup and tracert. What doesn't work is going into the browser through Firefox or Chrome and trying to visit a website. A coection is established, but pages never load.

Every other device I have can coect to the inteet. I took advantage of this by using an old Android Device and using it to serve as a WiFi bridge using USB tethering. With that, I can easily get online and my speeds are reasonable.

I thought that this was indicative that I had a bad wireless adapter, but I don't think so for two reasons now:

1. I can coect to other, far-away networks using my built in adapter (even though their signals come and go).
2. A new USB network adapter I bought yesterday works on other devices but not on my desktop. It has the exact same issue as my built-in adapter.

I have Private Inteet Access installed, but it never confounded anything before and it doesn't impact my coection if I use my Android Device.

What do you think the cause is, and do you think I can get around it? Is it possible that Comcast is blocking my machine for some reason?