RealPlayer refuses to play unless I sign up for $50 RealPlayer Plus?

I have had this PC computer for about a year.

I never played a DVD, I put one in and was given a choice to open with either realPlayer or ?????.

I choose realPlayer. I don't know why, I just woke up and hadn't had my first cup of coffee. There was also a box 'conveniently' clicked for me "Always open this type of file with" Before I could 'uncheck' it, realPlayer opened. Now, when I try to open any DVD it automatically goes to realPlayer. That's a bummer because...

realPlayer refuses to play the media. First I am given an option to buy an upgrade to realPlayer Plus 16 for $50, when I choose "no thanks" another widow opens that wants all my info to try realPlayer Plus 16 free (then they will charge?). closing this window brings me back to start, I try to play the DVD, I am prompted to buy realPlayer Plus 16, and on and on.

I am unable to do ANYTHING on that page but sign up. In other words realPlayer refuses to play my DVD unless I pay and sign up for an offer, like signing up to hulu or buying some junk I don't need.

This is what I hate about Windows, I had a mac, you insert the DVD and it plays. Simple. With Windows I had to create a desktop shortcut just so I could open the dang hanger door for the CD/DVD drive. What is this world coming to when you buy a computer with a DVD drive only to find out you need to pay $50 every 6 months just to use the dang thing?

I have been unable to find any way to play my DVD on realPlayer without paying their upgrade extortion fee. If you know how to do this, please do tell.

I am wondering if anyone can help me locate the options window where I can choose the other option for playing DVDs, rather than using realPlayer. OS: Windows 7 Home Premium.