installed latest version of flashplayer (17). Neither Explorer nor Chrome will recognize it. How can I fix this or how can I go back to a previous version?
Please don't post duplicate posts for the same issue. It results in us responding to the same issue/user multiple times. I've deleted your other post at https://forums.adobe.com/message/7551249#7551249.
Firstly, what OS is this?
Google Chrome embeds Flash Player and you don't need to download a separate version for it. Please check chrome://plugins and look for Flash Player. Ensure that it has not been disabled.
There are various Flash Player installers for the various browser (ActiveX, Firefox, Opera). Did you download the correct version for your browser?
Please go to C:\Windows\System32\Macromed\Flash and take a screenshot of the contents of the directory and post it here. See the FAQ The specified item was not found. for instructions. If this is a 64-bit OS, also post a screenshot of the contents of the C:\Windows\SysWOW64\Macromed\Flash directory.