Your original problem is a common one.
Changing the settings for the Graphics card is a solution for "normal"
programs, but may not be appropriate for a game.
Many of the games have a setup screen that allows settings to be optimized
for the game.
Some graphics cards have utilities that allow you make specific settings for
each program or game.

It would be a very good idea to read any manuals and help files that pertain
to your graphics card.
Since you did not identify which graphics card and display is involved,
specific help is a little hard to give.

It sounds like you right clicked on the display in the background area, then
on the properties selection in the pop up menu.
Then you clocked on a settings tab in the properties window. this produced a
display related window with a button labelled Advanced.  This causes a Plug
& Play and graphics card window to open.  The tabs allow different areas to
open that relate to the display.  From this point, the choices vary for
different video cards.
When I get to the right place, my card has a series of choices that allow
you to select a program, and the video settings to be used for a specified
program or global, and a specifc display model.

Are there no buttons or settings on the monitor to increase the brightness?
How old is the monitor.... they go dimmer with age.