If you are experiencing Bad Framerates, or crashing and you have a multi-core machine there are two things you can try.
1) Enable the console and type the command 'mat_queue_mode 0' which will disable multi-core support. It defaults normally to -1 which means activate if available support.
2) If that somehow still does not work for you, when you start the game bring up the task manager and set the affinity of the hl2.exe process to 1
If you are having the issue of not seeing any servers in the browser there are a few steps you can take that should solve the problem
1) Press the Stop Refresh button, then uncheck show map list. Be sure you are on the Internet tab of the browser and hit refresh now.
2) If that didn't work exit the game and in the steam gui you will see a globe icon with servers label. Click that and change the filter in that browser to Pirates, Vikings, and Knights II and hit refresh. You should now see servers and once you join one through this gui the in-game browser should start working again.
For the account is in use elsewhere you need to exit steam and the game completely and navigate to your steam directory. In this directory is a file called clientregistry.blob which is a temporary type of file steam uses for different things. One of the things it is used for is to keep the password remembered if you check that box; so make sure you know your password.
1)Delete this clientregistry.blob, and start up steam.
2)Steam will have to do some updates and then it will ask you for your password.
3)Start the game and join a server and you should not be getting this issue anymore.