I have a 2010 HP Envy 14 which has a hybrid Intel HD IGP/ AMD 5650 Discrete GPU running on Windows 8.
Off late, my laptop has had problems overheating, which was a result of the system fan not working. During the process of "verifying" that the system fan was not working, my Windows 8 install crashed bad and I had to do a fresh install of Windows 8, bringing it to a clean slate state.
Post the Windows install, I proceeded to install AMD Catalyst 12.11 beta drivers(since HP's official's drivers aren't and will never be updated) and I noticed that midway during the install, the laptop display was switched off. After waiting for 5 minutes, I rebooted my system, only to find the same result – the laptop display simply won't turn on.
If I put the laptop to sleep and then wake it up, the display is turned on momentarily, and then it gets switched off. From this, I deduced that the moment AMD drivers are enabled, the display gets turned off. To confirm: I booted into safe mode, disabled the 5650 drivers, rebooted back to normal and the laptop display is perfectly fine. The moment I enable the AMD 5650 drivers, the laptop display gets switched off.
Why is this display getting turned off post the fresh install? I don't believe the beta drivers aren't to blame since the same set of display drivers worked perfectly prior to the fresh install.
I should mention that while the initial Windows 8 install was broken I was running on Linux Mint for a bit and was playing around with VGA switcheroo, trying to get it working. Without the AMD drivers, there's no way I can get the HDMI out working and I need the HDMI out since I have a multiple-display extended desktop system.
Has VGA switcheroo caused the discrete display to be turned off?