Since your problems seems fairly unique, I've branched it into it's own discussion so that we can discuss it in more detail.
You've attempted to install using the offline installers for Windows, and it's not working, but you didn't give me much more to go on, so I can't really provide any useful advice.
A description of what you do and what fails would be useful, as would the contents of your installation logs. They should be at C:\Windows\System32\Macromed\Flash\FlashInstall.log and C:\Windows\SYSWOW64\Macromed\Flash\FlashInstall.log. Feel free to either just copy and paste the contents, or put them up on Adobe Send/dropbox/pastebin/etc and provide links. Whatever is easiest for you.