Connecting to Steam issue

I keep trying to Play my Steam games but when I do I get a message that says "Unable to connect to the Steam network. 'Offline mode' is unavailable because there is no Steam login information stored on this computer. You will not be able to use Steam until you can connect to the steam network again" I think the reason I get this is because I recently had a message from my computer that said Steam wanted to connect to my computer but I declined. Has anyone else had this issue and if so, how did you go about fixing it?

edit: Also, when I log in on the website, right next to my name there is an option that says "install Steam" does this mean it somehow uninstalled and needs re-installed? or does that appear even if you do have it?

Check your Windows Firewall in Control Panel as Steam must be allowed as an exception to have incoming and outgoing connections to the internet.

Edit: That's probably what you declined. You can always try uninstalling and reinstalling steam but you'll want to make sure and backup your steamapps folder as that's where all your downloaded content is.

thanks, how would I check to see if they are backed up?

Alright, thank you very much for your help! :)