Windows 8 / RT enable Flash in Metro Internet Explorer 10

- Goto the Windows 8 desktop
- Press Windows+R and type regedit & press enter
- Goto HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer
- Right click Internet Explorer and New / Key & call it Flash
- Right click Flash and New / String value named DebugDomain
- Double click DebugDomain and type the domain (eg google.com)
- Do not add www or https:// or http://

You can also edit the following file;

C:\Users\[USER_NAME]\AppData\Local\Microsoft\Internet Explorer\IECompatData\iecompatdata.xml

Please make sure you backup your settings etc. before trying this.