Trocha som po-googlil a našiel toto...prekladať sa mi to nechcelo sorry
Try deleting everything EXCEPT steam.exe and the steamapps folder and re-run steam.
Also it looks like a connection issue, which might mean Steam is blocked. Are you at a school/workplace or attempting to run Steam through a 3G card of some kind?
Also see if Steam is running in compatibility mode
Usually this is also because either there's a anti-virus program blocking, or the router firewall, or a local windows firewall is blocking the app.