How can I reset association of my Adobe ID with all computers and devices, so I can restart from scr

Do you mean (1) you have run out of devices on your ID and need to have them reset.  see 1~~ below

Or (2) you want to use a new ID on all devices ... don't forget you will lose access to all books using the old ID if you do this. see 2 ~~~ below

1 ~~~~

Adobe Live Chat: http://www.adobe.com/support/chat/ivrchat.html,

or as a slight short cut try http://helpx.adobe.com/contact.html?product=digital-editions&topic=using-my-product-or-service

Click on 'I still need help' and then you should see 'Chat with an Agent' at the bottom of the page.

'Ask our experts' will indeed just lead you back to this forum.

Sometimes you will get ‘Sorry! All agents are busy— please check back soon.’

Don’t refresh the page, just hang on and it should eventually go to ‘Chat Now, and agent is available’.

They can reset your authorizations, and then you must reauthorize any devices you still need.

(Unfortunately, Adobe haven’t got round to an admin website for viewing and editing authorizations.)

Some of the representatives haven't been properly trained and don't know what to do (and claim there is nothing they can do);

in that case the only way seems to be to give up that chat and try another session hoping for a properly trained representative.

If your problem is with another device using Overdrive, Bluefire, Aldiko or similar third party app, it is recommended not to mention that app when on the chat, just mention that you have run out of authorizations  (E_ACT_TOO_MANY_ACTIVATIONS) .  Thanks to AJP_Bear for that tip.

2 ~~~~

To deactivate ADE on computer, use ctrl-shift-D (cmd-shift-D on Mac)

To deactivate ADE on a dedicated eReader device, use ctrl-shift-D to ADE while the device is plugged in (cmd-shift-E on NMac)

To deactivate ADE on a tablet, see the help for the ereader app you are suing on that tablet.