The Adobe Flash player plugin is widely used all over the Internet, so it’s almost crucial that you install the Flash plugin for Google Chrome if you wish to maximize your browser experience. If you’ve been prompted to install the Flash plugin but nothing happens, then you’ll need to manually install it yourself. The installation procedure is pretty straightforward.
Here’s how you get round that.
1. Download this flash player xpi file.
2. Then rename it to .zip. It’s a special archive file of only the plug-in bit of the flash player app from adobe that interacts with your browser.
3. Extract it with Winzip .
4. Grab the flashplayer.xpt and NPSWF32.dll files. Copy them (Right click, copy)
5. Head to C/Documents and settings/”YOUR USER NAME”/Local Settings/Application Data/Google/Chrome/Application/Plugins/ and copy your files in there.
You can avoid having to unhide hidden files in Windows Explorer simply by copying and pasting the directory path provided above into the path bar.
6. Close and restart Chrome.
7.Now you should be able to watch YouTube videos to see if it worked. Or just come back to this
[Thanks to Blogote]