I didn't participate in the AHIII betas at all, and am trying to get back into AH after a long time off. I downloaded the full download package from the web site today. When I try to run it, it crashes (xxx has stopped working) almost immediately. I saw in some posts there should be a temp folder in the AH3 directory in program files, with a log, but it seems to have died before it even created that folder. 
I tried both the DX9 and DX11 versions of the exe, but both do the same thing. 
It looks like my PC is still vaguely ok for at least minimal experience. 
System info from DXDIag:
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  Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_ldr.160408-2045)
           Language: English (Regional Setting: English)
          Processor: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz (4 CPUs), ~3.3GHz
             Memory: 4096MB RAM
    DirectX Version: DirectX 11
          Card name: AMD Radeon HD 5700 Series
       Manufacturer: Advanced Micro Devices, Inc.
          Chip type: AMD Radeon Graphics Processor (0x68B8)
           DAC type: Internal DAC(400MHz)
         Device Key: Enum\PCI\VEN_1002&DEV_68B8&SUBSYS_21D71458&REV_00
     Display Memory: 2796 MB
   Dedicated Memory: 1014 MB
      Shared Memory: 1782 MB
       Current Mode: 1920 x 1080 (32 bit) (60Hz)
       Monitor Name: Generic PnP Monitor
      Monitor Model: E421VA
         Monitor Id: VIZ0072
        Native Mode: 1920 x 1080(p) (59.991Hz)
        Output Type: HD15
        Driver Name: aticfx64.dll,aticfx64.dll,aticfx64.dll,aticfx32,aticfx32,aticfx32,atiumd64.dll,atidxx64.dll,atidxx64.dll,atiumdag,atidxx32,atidxx32,atiumdva,atiumd6a.cap,atitmm64.dll
Driver File Version: 8.17.0010.1404 (English)
     Driver Version: 15.200.1062.1004
        DDI Version: 11
       Driver Model: WDDM 1.1
  Driver Attributes: Final Retail
   Driver Date/Size: 8/4/2015 01:28:34, 1445224 bytes