Is there a way to remove password protect from pdf

[lan0.sky0]

Hi,everyone!
I am a student of University.I pay $85 for each of my ebooks and have my UoP password and username to open them.
The problem is that I want to move them to my kindle dx which does not support the password part of the pdf file.How can I remove the password protect from this file.Each page is password protected, but I only have to put in my password one time and it opens the whole ebook.However, on the kindle dx, the cursor does not go to the username or password box, so i can't open it on my kindle.I tried buying and using a PDF restrictions remover but all it does is say "Restrictions Removed" but the password protect is still on when I transfer it to the kindle.
Any suggestions of what product to use or what to do?
Pls help!!!
Thank you so much in advance.

[Unregistered]

I've used this firefox extension in the past. It is designed to allow you to "edit" pdf files on-line, but I discovered that by opening and saving PDF files with it - it removes the security features in the process... I haven't used it in a while, but give it a try... It's called PDF Escape - by "Red Software". Requires firefox browser.