TF2 won't fully start

Alright. During one offline game, (just looking at some new maps I dl'd) TF2 proceeded to bug out and began to freeze up every few seconds. At that point I quit the game, and then restarted my computer. Upon later restarting TF2, it never got past the opening screen (artwork of 3 or 4 members of red team, loading box still in the lower right corner, mouse still functioning) but it never froze or gave an error message. I tried again, but with the '-window' startup mode, same thing. I fully uninstalled TF2 and reinstalled it. Still, same thing. Any ideas?

There was something about deleting the registry.blob.
Oh, and I had the same problem when I did something in my custom cfgs. Have you been messing around with them?

I didn't do a damn thing to any of the files, other than put some custom maps into the maps folder. It really has me annoyed, since I now have about 50 awesome looking maps that I can't even play.

Alright, I went into C:\Program Files\Steam\SteamApps\sever323\team fortress 2 and deleted the TF2 folder, as well as the 3 TF2 GCF's located at C:\Program Files\Steam\SteamApps, and then reinstalled/reupdated TF2. Same problem. Does anyone have any ideas whatsoever as to how I can fix this? any specific things I can do? Should I just completely delete C:\Program Files\Steam and reinstall everything?

You should have deleted ClientRegistry.blob like MNC said, I had to do that just so I could play mods.

Fixed - After removing the ClientRegistry.blob and having it fail to properly start again, I just physically deleted everything in the Steam folder and any other files exclusively pertaining to Steam and did a clean download. Thanks for the suggestions, though.