A few year back I installed adobe digital editions on my laptop and purchased some ebooks.
Since the I have switched to a new laptop which I copied all my ebooks too at the time.
Today I installed the latest digital editions in order to read one of this ebooks but I cannot open the book and there is a message saying that the book is authorized to a vendor Id which I have no clue what it is as a few years have passed since I purchased it.
If you not know which adobe ID used for authorisation can not open the eBook. Has you try to ask the reseller of the eBook to check wihch ID was used for the eBooks?