If c0000005 error occurs even after changing the DEP settings, manually reset them in the registry. I've seen threads state that restarts are required, but this is false. This error was happening to me, and a manual reset solved the issue.
The DEP data is held in the Registry at:
You should see an entry for Diablo II.exe with a value of DisableNXShowUI. If it's value is anything other than this, replace it. Since my install is in F:\Diablo II, it should look like this:
NAME, TYPE, DATA
F:\Diablo II\Diablo II.exe, REG_SZ, DisableNXShowUI
F:\Diablo II\Game.exe, REG_SZ, DisableNXShowUI