I probably should have responded to N19h7m4r3. I am understandably very frustrated that I am completely unable to use my Steam purchases and it isn't exactly helpful when someone appears to be suggesting you are ranting everytime something goes wrong and not trying or capable of working through the issues like them.
No worries, mate and I wasn't committing in regards to you at all. It's mostly to two other members here that seem to fervently go after anyone that seems to be okay with Steam or any other client, along with the client themselves. Easily seen by some threads that crop up here lately.
In fact, it makes me rarely want to frequent the forums section despite being on extremely good terms with the majority, and developers.
Sadly in your case I've never heard of anyone with such an issue relating to Steam, and can only tell you to do the basics which I assume you already did.
Tried closing it, reopening.
Moving the game's folders out, rebooting, and moving back in, then starting Steam.
Making sure the client is up to date, same for OS.
Making a new User account to see if the issue persists there. If it does not, it most likely means an issue with your regular account.
Cleaning them out, and reinstalling.
In relation to not being able to log into the support page for Steam, they use a different user account for Support compared to your regular Steam account. You'll most likely need to make a new one there.