So I've seen a few solutions being bounced around here regarding EE and DXWnd and I just wanted to pipe up with my own more elegant solution that doesn't require DXWnd to be running each time.

1. Download dgVoodoo 2 (http://www.dege.freeweb.hu/dgVoodoo2/dgVoodoo2.html). This was tested with 2.63.1.
2. Copy the DLLs from the x86 folder, dgVoodoo.conf and dgVoodooCpl.exe into the "aphavoc" directory for AvH or into the "cohokum" directory for CvH. Bear in mind that a lot of antivirus solutions and SmartScreen seem to flag up dgVoodoo as untrustworthy. Nobody knows why.
3. Right-click on the game executable, then on "Change settings for all users". Untick Win98 compatibility and administrator rights (they're no longer necessary and they interfere with dgVoodoo). Do the same for local user compatibility settings if they're still set.
(Optional) 4. Open dgVoodooCpl.exe. In the General tab, select Full Screen and "Stretched, 4:3 Aspect Ratio". In the DirectX tab. Feel free to up the resolution to a 4:3 resolution of your choice (ideally 1440x1080). You can also increase the anisotropic filtering, but MSAA causes some weird glitches at my end on the title screen.

THANK YOU!!

I was almost tearing my hair out trying to get this beast running again. Your instructions worked 100%, though the DirectX tab would only let me select 1440x900 (which is 8:5 resolution? wtf is that?) as the closest I could get to 1440x1080 - but the game actually friggin ran and played. Many thanks!