I am using an HP ProBook 4540s with Windows 7 Professional as the OS. Specs can be found here. The issue began when pressure was applied to the laptop body (on the front edge and the back of the display/lid) during use. The screen would go entirely white. Could originally be corrected by closing and opening the laptop 3-10 times successively.
Presently, the display will work perfectly during booting up and logging on, but as soon as Windows finishes loading, the display goes white. Connecting an external monitor and having the display config. set to extend or share screens allows for both the laptop and external monitors to work normally. Disconnecting the external monitor causes the laptop display to go entirely white again.
Shaking device while inverted momentarily restores the display to working order, goes white when upright again. This only rarely works now.
Graphics cards are Radeon hd 7650M as well as Intel(R) HD Graphics 4000. Drivers appear up to date. On the Intel card, atikmpag.sys is not digitally signed, but driver updates do not sign it.
The graphics cards appear to be interfering with each other when only using the laptop display. Disabling either graphics card causes the laptop display to function normally, but disables the external monitor. While only one graphics card is running, the laptop does not recognize any external monitor connected to it. While one card is running, the laptop display can work without being connected to another monitor.
Booting up the laptop with Linux via an external drive causes the display to function without error.
My goal is to get the laptop display to work normally while running Windows 7 professional and to no longer necessitate the use of an additional monitor while having both graphics cards running. How would I go about correcting this issue?