I found this problem in the steam forum....
When i open steam there is a box that says updating steam and it is stuck at nothing. What do i do?
Your internet connection is messed up. Steam can get a connection but can't transfer data. Make sure your firewall isn't blocking some of Steams ports or that somewhere else on your network is like your router or ISP.
I see this problem when I'm connecting to a captive portal like pay wifi. Steam sees that there is internet access but it can't connect until I open Firefox and login into the wifi.