I know of only one way that this can happen in windows, and has nothing to do with Steam other than their not-so-great decision to install all content into Program Files.
If you are on Windows 7 or Windows Vista, and you have UAC set to ON, then change it later to OFF, this can happen.
UAC does thing evil thing where if a program tries to write to a "protected" area like Program Files, EVEN IF YOU ARE ADMINISTRATOR, when you get a UAC prompt and give permission, it actually writes any files that would normally go into that directory into a "virtualized" directory somewhere else.
If you turn off UAC, that will no longer happen, and as an awesome bonus, it will no longer know about the files that it virtualized.
So in your case, if you had UAC on, installed a ton of games, then later got sick of UAC and turned it off, this would happen as you described.
See the second paragraph in "Features" in the article on User Account Control.
If you have done this and turn on UAC again, your content will come back, but be a TOTAL mess because if you've downloaded more stuff with UAC off, then that will be invisible when you turn UAC on, and vice versa.
this drove me a little crazy once before I realized what was happening.
i'm curious to know if this is your issue.
Well, one way to regain access is to reset your password. If Steam Guard did make some server-side error, password reset emails should be unaffected. Once one arrives, reset your password to the same one (Steam doesn't check for previously-used passwords) and that will bypass Steam Guard. Once you're in, try disabling and re-enabling Steam Guard from Steam's settings. Then try logging out and back in to make sure Steam Guard emails are now sent.
Best Answer
Tickets take time. Give it up to 3-4 working days. They will probably require a scan of a retail box's serial with the ticket number or another form of verification before resetting anything thought.