Windows Vista Windows 7 wont let programs use internet

[Windows 7 sux]

Yeah i dont really know how Windows 7 works but it wont let certain programs use the internet like Firefox, Chrome, Aim, Hotmail, Guild Wars. When I open up Firefox or Chrome, it says it cannot connect to server. What it does allow is Internet Explorer to use the internet. Can someone help me out here? Any help is appreciated!

 

[reghakr]

Do you have a firewall?

Was this a "clean" install or an upgrade?

Did this occur immediately after install?

 

[Saltgrass]

What firewall are you using? If you are using the windows firewall, did you change any settings or see any messages?