Both ADE 2.0 and the older 1.7.2 work on Windows 8.
ADE 2.0 has some bugs that prevent it working well in some cases (most connected to certain devices and to Overdrive).
If ADE does not launch, it is probably because the file type registrations didn't get properly made.
Try an 'Open With' on .acsm and .epub files, and force them to open with ADE.
(Can't give more details now, post again if you need help with that).