How can I fix this "Adobe two-version" problem, so only the latest version stays enabled, the old version stays DISABLED, and/or uninstall the old version?

Question

I went to my add-ons tab, and I DO, in fact, have two versions of shockwave flash, an 11.9...version, and a 13.9..., which, if I'm not mistaken, is the latest version. There is a "ask to activate, always activate, never activate" button for EVERY add-on. I clicked never activate on the older version, and closed the tab. I then tried to play a video off of the Web. It would not play, I tried another site with the same result, so I went back to my add-on tab, and the button for the older version had changed back to "always activate" by itself. It continues to repeat this, and WILL NOT stay on "never activate". Every few times I return to the add-ons page, THE NEW VERSION IS DISABLED, AS WELL AS THE OLD ONE. I've tried to uninstall the old version, but when I go through control panel, and bring up the folder contents, the old version isn't even there! I've done start, find, and typed in "Adobe", and the old version is NOT FOUND! Both versions keep changing back and forth on the activate button, and they both will disable on their own, no matter how many times I fix it! smh!!

Answer 1

@jscher2000: Didn't mean to lose contact. I still don't have my playback problem solved, if you can believe that. I've downloaded the uninstaller / installer links with someones help that's on this forum, used them in the exact same order. It did nothing to help. However, I was in the process of attempting your solution. I made sure all browsers were closed; in fact, I went offline before this procedure. When I used find, and typed in Shockwave, it came back..."no search results". I recalled a path I had previously used, and had to use it instead of find, C:/ Acer/ Windows/SysWOW64/ Macromed/ and here there were files for Shockwave AND Flash. I opened Shockwave, says " this folder is empty". Flash Player and Flash Util plugin, Util32 Active X, NPSWF32_13_0_0_214.dll...all files appear correct, BUT why aren't there ANY files in the Shockwave folder? NONE of the buttons you describe in your steps to let Firefox "clean up" the pluginreg.dat file show in my window...if I am in the right window. My username is at the top, and it's drop-down is "3 button"+sign out. One says settings, but it doesn't take me to any "help", Trobleshooting info, "show folder", nor any way to exit Firefox or to start it back up. Settings goes to "edit settings", and has a list of checkboxes...all with something to do with threads in one aspect or another, and one concerning private messages. Sounds to me like I don't know what I'm doing, am on entirely the wrong Mozilla /Firefox page, and I'm NEVER, EVER going to get this damn video playback crap fixed once and for all. Some sites will let a video play, but they are rare. Vikings.com is the one that has me red-faced. NOTHING plays there. Except ads, of course. You can't get those to STOP.