I branched your post to a new discussion as you're issue, based on your description, is not the same as the OP. Unfortunately, Adobe cannot guarantee the authenticity of Flash Player installers posted to non-Adobe sites. Official Flash Player installers will not lock up your system the way that you describe.
centurylink.net went into their internet speed test page, and it had listed that we could not do a speed test unless we had the flash player update, and to download the player from listed on bottom of their page. Go into Centurylink.com got to top of page ,
customer support click on internet ,go into that page and over on left click on speed test, go into that, and click on number #2, speed test and their you will see what I am talking about.
It's always best to post direct links to pages, versus having us attempt to find the correct page. Is this the page you are referring to Speed Test CenturyLink with option 2 selected, I see links to Adobe's site to download the installer.
However, the behaviour you are describing (system locked up) would not be as a result of the Flash Player installation. When you restart your system to you have the 'Reopen windows when logging back in' check-box selected?
Please describe the behaviour in a more concise way (we can't see what you're seeing) and post screenshots to demonstrate what you are seeing/behaviour observed.. See How do I attach a screenshot? for assistance in taking and posting screenshots.