Connection timing out when network is just fine

My latop using windows 7 while at work is not letting me on 99% of the websites. I am using firefox and chrome to connect and neither worked. My cell phone, my coworkers cell phones, their computers (hardwired) are all working fine. Only the laptops on wifi have connection time out issues. All browsers are configured to detect proxies automatically. My laptop is only running windows security essentials. I have turned all uac and firewalls off. Currently the only pages I can seem to pull up are google homepage and yahoo homepage. I can still send a few emails using thunderbird however, only email accounts with the servers on yahoo, gmail, and outlook work. Any other domain name emails do not. I have tried to reset both modem and router and it only helps for a couple minutes before returning. My other coworkers have used their wifi connections on their laptops on some get the same problem and some dont.

Any suggestions?

Update: I have tried turning off the tcp/ipv6 protocol that helped a little on.a few websites, even then iffy at best. Attempted a system restore to the last date of an update before this problem occured, that did nothing as well.

Would really appreciate some help....