You can switch between Adobe ID's in ADE, so you may not need to reinstall
(which can screw everything up, because unless you remove certain files,
ADE will use them, rather than recreate them. That's both a benefit and a
handicap, depending on what you're trying to do. Just deauthorize the
computer with the CtlShiftD key sequence, and then go to Library view,
click on the small arrow next to the word 'Library', and pick 'Authorize
Computer' from the drop-down menu that will appear. Try it first, to see
if it will do what you think you need to do.
Now for the bad news. The way ADE works is to associate whatever ebooks
you download with the ID in use at the time (you can get a good
understanding of this from ADE Help - F1 key from Library or Reading
view). So, you cannot access ebooks you downloaded under one Adobe ID from
another Adobe ID. That's part of the implementation of digital rights -
DRM for short.
You can transfer files from one PC to another. That's covered also in the
Help files. Just remember that the ID's must be the same ones....
You can delete them from ADE if you can see them in ADE (which means that
you're using the ID you had when you downloaded them). In Library mode,
you can click on the arrow next to the name of the ebook, and the drop-down
menu will give you a choice to delete them.
This is one at a time - sorry!