I cant play fullscreen :/

[PudgeWorthy]

This is a big problem, and I have just discovered its outside of steam as well
Some games start up fullscreen (i.e archage) so I cannot actually get into the settings to change it to windowed.
When it starts, my main screen goes black and starts flickering, then it reverts back to desktop
This also happens for a couple of other games, and also with tf2 if I tab out, I cannot tab back in.
Halp

[newgraund.DLL #DOOM/E1M1]

-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.
-fullscreen - Forces the engine to start in fullscreen mode.
-windowed or -sw - Forces the engine to start in windowed mode.

***How To Set Launch Options***

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

More Launch Options @ https://support.steampowered.com/kb_article.php?ref=1040-JWMT-2947