So I have this Dell Latitude E6540 that apparently has two GPUs: Intel HD4600 and AMD HD 8790M). This seems like a really stupid design, but I assume the Intel GPU is integrated into the CPU or chipset somehow and it isn't powerful enough so they threw in the AMD.

When I first acquired this thing, I installed both the Intel and AMD drivers needed to enable BOINC to crunch on the GPUs. And it worked for a couple of months. Both GPUs got used by various projects. However, I kept having issues every few weeks with the HDMI port just quitting working, which is mission-critical for this laptop. Each time, I would have to reinstall the AMD drivers and CCC to make it work again. Now the whole thing is a mess. The AMD GPU is completely unrecognized in the device manager, showing as "Standard VGA graphics adapter". All Start Menu links to both the AMD and Intel graphics controls were gone, although the programs were still installed and I could launch them by CLI. So I unistalled ALL video drivers, used the AMD clean uninstall program, and reinstalled everything again. The Intel GPU is working. The AMD one is not. I tried the beta drver, to no effect. I tried the official Dell driver...nope.

Can anyone help me?

Dell Latitude E6540
Core i7-4600M
Win 7 x32