copy paste dysfunction

I am using adobe digital editions 4.5.11. in my laptop which my university gave me. we as a school purchased a book from e-book central and in order to open the book we need use adobe digital edition program (unfortunately). I used to use the program with its all features yet one day the copy function started not to work. the feature came and went back couple of times and now it is all gone. no matter how many times I install the program and download the e-book, that function did not come back. I tried the get help from adobe chat yet it was useless. My adobe case is ADB-25921748-H5B0. I assume I use the paid version of the program since it comes as a default program with the laptop that school gives. You can get me in contact through my e-mail