Downloaded installer 1/18/2-forge-40.0.4

Double clicked installer in downloads folder

"Install Client" is selected.

Selected "C:\Users\Dame Bella\AppData\Roaming\.minecraft\mods"

Got message "The directory is missing a launcher profile. Please run the launcher first!"

..... 

So when I install it into the .minecraft folder itself it goes through the install process and says it was successfully installed into launcher, but the game crashes when I try to open the game.

 

5 hours ago, bellasita said:

Selected "C:\Users\Dame Bella\AppData\Roaming\.minecraft\mods"

Of course, you are not supposed to install it into the mods folder...

 

5 hours ago, bellasita said:

the game crashes when I try to open the game.

Logs or it didn't happen. Without logs, there nothing we can do.