Why windows is refusing to run firefox

What firewall are you using?
Are you using a security suite like Norton?

Your problem is that something on your computer is blocking access to the net for Firefox

have you read .....

Connection issues: Can't connect? Getting messages such as "This document contains no data" or "The connection was refused when attempting to contact..."
http://forums.mozillazine.org/viewtopic.php?t=258042

Error loading any website
http://kb.mozillazine.org/Error_loading_any_website#

How to configure Norton Internet Security (NIS)
http://forums.mozillazine.org/viewtopic.php?t=259337

Firefox 1.0.6 - Installation Guidelines & Release notes
http://forums.mozillazine.org/viewtopic.php?t=294709

if you are using zonealarm ... make sure that you have the most current version

a quick fiz is to uninstall your firewall software and then reinstall it ... this should force it to read all your current software ...

I am assuming that you have check your computer for spyware

I found how to fix the problem that is preventing firefox or opera to run .

It could be some sort of information that is stuck in the antivirus or in windows itself.

So for that reason rename your firefox.Exe , or opera.Exe in program files, to what ever youwant ,example: myfirefox.Exe ,or opera2.Exe .

And this will make them run again!