Set the resolution too high and cant see anything?
Sometimes we try different resolutions to see which one suits us best but that may turn into a problem in which you cant even see your menu buttons, therefore changing resolution through menu also become impossible.
Don't worry there is a very simple solution for this problem, you are just going to set some launch options.
Cant change your resolution back to normal?
This is gonna help..
1. Right click on CS 1.6 in steam Games window.
2. Click "properties" and then choose "set launch options".
3. Type in "-w 800 -h 640" and enter.
Start your CS again and see that your problem has been solved, you can check your Resolution is set to 800x640 now you can change it as per your requirement in your old way.
Don't know how to set Launch Options see here -> How to Set Launch Options
For Non-Steamers:1. Right click on "CS 1.6 icon", go to properties and look in the target window. It should look like
"C:\installation Directory\Counter-Strike 1.6\hl.exe"
2. Outside of the quotation marks type
-width 800 -height 640
Now it should now look like this
"C:\Installation Directory\Counter-Strike 1.6\hl.exe" -width 800 -height 640
3. Now your CS starts in normal mode and you can access to whatever resolution you want.
NOTE: Finally remove "-width 800 -height 640" otherwise CS will start in 800x640 resolution everytime
That should re-store the game to its original configurations.