I'm going to bump this thread instead of making a new one to ask a related question.
This problem I ended up resolving by myself; apparently Vmware Workstation created it's own network on 192.168.1.56, and srcds decided to use it.
I had a perfectly working server before I reinstalled windows 7 on Saturday. Now, using the exact same settings, it's either I can connect, or other people can connect, and I can't. When it does start up, it starts on port 27016 instead of the set 27015.
And ideas this time around?