Application Initialization Error

disable any realtime anti-virus/adware/network control applications

Make sure you are not running any traffic interception tools or proxies like Fiddler.

Ive notice that when I downloaded the file, only 1.1mb when the actual file is 20mb

The installer you are downloading is the online/web installer.  It's a shim installer that downloads and installs Flash Player, and any 3rd party offer you may have elected to install, silently in the background.

To investigate the error, I'll need to get the installation log files from you to troubleshoot the 'application initialization error'.  Please review the FAQ Where do I find the Flash Player installation log on Windows? and provide all files listed: FlashInstall32.log, FlashInstall64.log, Adobe_ADM.log and Adobe_GDE.log, so that we can troubleshoot the issue.  After gathering the files, upload them to cloud.acrobat.com/send using the instructions at How to share a document and post the link to the uploaded files in your reply.