Can you be a bit more specific as to what you are trying to do, and the problem you are having? Are you trying to copy information FROM a .PDF to something else? You can't do that with the Reader only, as essentially you would have to save changes to the .PDF to "cut" from it. Even if you don't save the change physically, you would be altering the contents of the file and need write access to do that.
It's not really a "thing that opens up within the browser", it's Adobe Reader.
By default, Adobe opens .PDFs within your browser. This also causes Adobe to hang in memory after you closet he .PDF most of the time. I recommend adjusting the setting, which can be done from within Reader...
Open Adobe, click Edit, Preferences, which I believe is also CTRL + K
Click the Internet title on the left frame, uncheck "Open PDF in Browser" or whatever it says. I can look when I get home, don't have Adobe on this PC.
I wasn't aware they had a try and buy version, but if you don't have the writer, A.K.A. Professional, you won't be able to do what you want. There are free .PDF programs out there though, such as http://www.cutepdf.com/