How do I mount an ISO file in Windows 2012 Server?

In general, if you have downloaded the ISO file on your computer, you just need to right-click it and select Mount ISO from the menu.

For more detailed information, please refer to the link below:

Mount a VHD or ISO File in Windows Server 2012 and Windows 8

How do I change password when connected to Remote Desktop on Windows Server 2012?

Press CRTL+ALT+END

this is in essence the same thing as CTRL+ALT+DEL, it will display the login security screen where you can change the password, lock the computer, shut down, etc.

If you are doing RDP within RDP then this might work for you:

Press WindowsKey+R (or get the Run box open) – then type OSK (It will open ‘on-screen-keyboard in your remote-remote session). Or open on-screen-keyboard in different way.
Then press on your physical keyboard (not on that on screen!!) ctrl and alt keys. Using your mouse tick DEL key on ‘On-screen-keyboard’.

From https://social.technet.microsoft.com/Forums/windowsserver/en-US/2b67fa96-707b-47c4-90f5-c3a087ba16a9/how-do-i-change-password-when-connected-to-remote-desktop: