Solved I just realized that I can connect only with Firefox

[IMAyNeed]

No other browser (IE, Opera) would work.

How? Why?

 

[DeaconFrost]

I've seen this behavior before when I virus/malware app altered the proxy settings of IE.

What happens when you try to run IE and open a web page?

 

[IMAyNeed]

After a restart, it got resolved.
The reason I posted the thread before the restart, as I asked in the post to learn how IE and Opera couldn't connect, but Firefox could.
After the diagnose at IE, it was saying that you are configured correctly, but the site seems not responding and that it could be firewall, but it wasn't firewall. I know my firewall settings.

Also, I just realized this:

This is from Uninstall a Program.

Why there is 2?
When I try to uninstall 4.0.1, it says close Firefox. But the opened firefox is 14.0.1.
???

I uninstalled 4.0.1 and 14.0.1 got uninstalled too. I installed it again, but my passwords from sync didn't come back although, my bookmarks came back????

I had to reset sync and remove this computer's data and get all data from my sync data.