This issue has been driving me mad for over a week now and after scouring the internet to no avail, I turn to you, the tom's Hardware community.
To start, my system is set up as follows:
Windows 7 Home Premium x64
AMD Athlon X4 640 @ 3.4ghz, 4gig RAM
ASRock M3A770DE AM3 AMD 770 Motherboard
GIGABYTE Radeon HD5770 running two LCD monitors; one via HDMI the 2nd via DVI. I am running the latest stable drivers from AMD.
When I power-on the system I get a mirrored display through the boot sequence until I reach the Windows login screen. At this point the second monitor goes to sleep like it isn't getting any input. The primary monitor displays the login screen in 640x480 resolution.
After logging in the desktop resolution will sometimes be set at 640x480 and sometimes in native resolution 1920x1080. It seems to be random but, either way the location of the icons are never where I left them; they're lined up as if they were reset.
When attempting to extend the desktop to my second monitor; it will allow me to select the option in both the AMD control panel and windows resolution window but, when clicking apply the primary monitor flashes but nothing changes (though it will ask me to confirm the settings are correct). The setting at this point shows 'display on monitor 1 only'.
I am able to mirror the two monitors, create an Eyefinity display, and set the 2nd monitor as primary. Regardless of which monitor is primary, I am unable to change the resolution of the second display.
Solutions I've tried:
Several attempts have been made at uninstalling all AMD software and drivers with their tool and/or driver sweeper via safe mode or normal login (normal login results in a blue screen, no surprise).
After sweeping or uninstalling I've tried several versions of AMD drivers with the same results.
I've also tried sweeping/uninstalling the AMD drivers and replacing the 5770 with an old Nvidia 9500GT running the monitors in the same configuration and installing the latest nvidia drivers software. I thought this was successful as I could extend the desktop after the nvidia driver installation. However, the problem persisted after rebooting the machine.
As both cards resulted in the same problems, it would seem to confirm there is a problem within Windows (or the Motherboard?).
As I've said previously, I've scoured the internet for answers. There are a couple very old similar posts on the AMD forums without any answers. I do not have Windows Live Mesh installed which is a common solution for similar problems.
I'm assuming there is a registry setting someplace that is causing all of this nonsense however I'm at a loss to where it might be (though not afraid to try possible editing solutions).
My next step is to wipe and reinstall windows, however I'm running an SSD with secondary storage and spending the hours to get it set up just right again (disabling services, re-pointing user folders, etc) is not at all appealing. I have the 'okay' from the wife to spend some $ on new hardware if I can prove there is a failure someplace.
Well, I think a place to start would be downloading an Ubuntu disk, so you can verify whether or not the issue is hardware or software, since Ubuntu will be able to use multi-monitor displays out of the box as long the hardware is fine.
Though, on the hardware side, I know say that you've changed which screen was primary before, but did you try physically switching the cables?