Which version of Windows do you have?
Can you take a screen shot of the graphics control panel?
Windows 8.1 is the version.
I have attached the display screen shots. Note in second picture the Display drop down has only 2 features, neither custom resolution. My computer has the custommodeapp.exe files available but cannot be opened, nothing happens when i double click on any of them???? I cant believe how a new computer can be so non user friendly.
If CustomModeapp.exe does not open is quiet expected if your computer manufacturer has blocked this feature through VBIOS. At this stage, your computer model does not support custom screen resolutions.