I had the same problem with my HD 7970 (received SYSTEM_THREAD_EXCEPTION_NOT_HANDLED by atikmpag.sys) and now found a solution:
1. Uninstall Lucid Virty MVP (if installed). This is usally active, if you upgraded to Windows 10 from Windows 8.1.
2. Install the AMD 15.6 Beta Driver for WIndows 8.1 from June22 "amd-catalyst-15.6-beta-software-suite-win8.1-64bit-june22".
Now your graphics adapter will be detected correctly and everything works fine.
The latest driver 15.7.1 is not working with my card and even after the solution, cannot be installed as Windows 10 tells me, that it is not suitable for this platform.