actually I found the problem to be the game.cfg once I deleted that everyone was able to see my servers. Even if its sv_lan 1 you should still be able to see it but when you join you will get an error. Just try deleting the game.cfg.
Hmm...First, try turning off any firewalls or routers completely. Then if that doesn't work, make sure your ISP allows you priviliges like playing online or running some programs. If you can join a server but can't create one, then my theory is wrong. Sry I can't be more help, y'know?