Resolution problems, how to fix?

An easily solvable problem, you can change the resolution to anything you want without loading the game.

Copied from the steam support website

Set Launch Options

1. Right-click on the game title under the My games tab in Steam and select Properties.
2. Under the General tab click the Set launch options... button.
3. Enter the launch options you wish to apply (be sure to separate each code with a space) and click OK.
4. Close the game's Properties window and launch the game.

Most Console Commands can function as a launch option by adding a "-" in front of the console command, but many of them do not make sense to use in this fashion. The most common launch options are listed below. Here are the commands you may want to try are

#-autoconfig - Restores video and performance settings to default for the current hardware detected. Ignores settings inside any .cfg files until this parameter is removed.
# -32bit - Forces the engine to start in 32-bit mode. Only useful on 64-bit Operating Systems. -64bit can also be explicitly stated for games that use the 64-bit Source engine, although it is the default.
# -fullscreen - Forces the engine to start in fullscreen mode.
# -windowed or -sw - Forces the engine to start in windowed mode.
# -w <width> - Forces the engine to start with resolution set to <width>.
# -h <height> - Forces the engine to start with resolution set to <height>. This launch option does not need to be set in the presence of -w. The width value with determine the height automatically.