My laptop screen turns yellow once the keyboard/mouse is touched?

I dont comprehend how the pressure causes it but you may try to reset the monitor settings to factory default if you have the option. It's a small chance that the screen refresh rate might have been changed. In order to lower it down depending on the OS it changes only guessing that's a vista or a win7 :
Apposite click on your desktop, screen resolution, advanced settings, display tab, screen refresh rate.
Try lowering it down and see if it helps.
But i presume you should stake this within electronics box as this is 95 % a hardware issue more like lcd display hardware issue.
Polite luck...