I'm running Firefox 26 and am trying to install Flash version 11.9.900.152. I keep getting this Error: Application currently in use and it fails to complete the install. I went to Adobe and found uninstall instructions and in the process of trying to uninstall Flash, I'm trying to delete all the files in the c:\Windows\SysWOW64\Macromed\Flash folder. I can get them all except: NPSWF32_11_9_900_152.dll, which produces the following error: the file is open in plugin container for Firefox How do I get this stopped so that I can update to the latest version of Flash? This is so darned frustrating.