Nook issues

I read what the previous poster said about the Nook. Now, I have another question. I am an graduate student. My current courses have ebooks. They are in pdf format. They are password protected, but I can open them up on my computer and mark it so I don't have to sign in. When I put them on my Nook, they won't let me in. It just says  "Protected pdf". I've called my school's tech support and Nook tech support. The Nook tech support sent me here, but it won't open on this format either. Does anyone have any ideas? I know the password. I just can't enter it in these documents.

Thanks.