Why after Downgrading IE10 to IE8 I lost access to Internet

I can open localhost pages hosted on my IIS, but I can no longer access google neither my company services.

What is the problem? By downgraded IE10 to IE8 I lost configurations?

Do you have any idea?

I compared my ProxyServer value on the registry key [HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionInteet Settings] with the one my colleague has and they are the same, still he can access everything but I can't.

Any clue? Thank you a lot!