help with DVD drive

I have had my DVD drive for a while, it played all movies fine. Then a little while ago I installed, uninstalled, reinstalled, etc. a few different DVD programs to try them out (Interactual, PowerDVD). With each one it asked me to register my location and things and then after that I started getting an error. I think the software thinks I am doing something illegal since I registered the location more than five or six times, I don't remember exactly what the error message said back then but it was something along the lines of registering too many times. I tried unplugging the DVD drive from the rest of the computer, restarting the computer, then plugging it back in and restarting again and now when I try to play DVDs it tells me "A CSS Error has occurred while trying to play the DVD. If you continue to receive this problem please try reinstalling your DVD navigator." I'm not sure what the DVD navigator is, and I'm not sure why it is giving me this error. And no, it wasn't because I was trying to copy or burn DVDs illegally, since my drive can only read and not write DVDs. Any suggestions? Thanks in advance
:just want to be able to watch DVDs :

 

Why does that matter though? Every time I registered it was the same region. And even if I did register it more than 5 times, why doesn't it let me play the DVDs? I think earlier when it gave me the error it suggested unplugging it and plugging it back in but that didn't appear to help. Thanks for your input