Unable to erase computer authorization in ADE 4.5 on Windows 10

[msrparulid]

I've wasted an hour of my Sunday scouring the forums for this and am at my wit's end. I'll try to be brief and concise as possible.

1. I bought an eBook from a publisher and the only way to download it is to open an ACSM file with ADE, which I already have installed on my Windows 10 PC.
2. Trying to open the ACSM file results in, "Error! Check Activation." I emailed the vendor about this and they wrote back saying I'd need to erase my existing computer authorization in ADE and re-authorize.
3. I tried de-authorizing my computer but get "Unable to Erase Authorization. Please try again after some time."
4. I've tried uninstalling and reinstalling ADE (once with CCleaner, twice using the ADE uninstall program in the Program Files directory). Problem not solved.
5. I tried implementing the Windows registry changes recommended here: https://forums.adobe.com/thread/2100206​. Problem not solved.

I'd appreciate hearing any success stories from folks who have successfully troubleshooted this.

[Nanaky]

Normal should remove the registry key solved the problem. Has you authorize Ade new after remove the key?

[msrparulid]

No, removing any of the registry keys doesn't solve the problem. I can't authorize ADE because I can't even erase my authorization. I'm pretty much resigned to eating the $5 I paid for the eBook.

[Nanaky]

You remove the right registry key?

[msrparulid]

I’m not sure. Adobe’s instructions aren’t all that clear. Which specific

file do I need to erase?

[Nanaky]

Windows:

    Close all applications.
    Press WINDOWS + R.
    In the Open text box, type regedit and then press Enter. The Registry Editor opens.
    In the left pane of the Registry Editor, locate the following registry key: HKEY_CURRENT_USER\Software\Adobe\Adept
    Remove the Adept Folder.
    In the Confirm Key Delete dialog, click OK.
    Close the Registry Editor.
    Open Adobe Digital Editions and reauthorize.