[quote]I think Win+P only supports two monitors?
No, this is not correct. It works for all 3. They won't be setup natively.
Change it to Computer Only, then set the resolution to the native resolution of one monitor. Use the CCC to choose your center monitor, or alternatively, swap cables to make it the center. From now on, leave the monitor cables as they are.
Now change it to Duplicate, and then create an Eyefinity group in the CCC in this setup. You should now be able to Windows-P between the two setups. I used to do this ALL the time.
Now change to Computer Only. Now change to Extended. Use the Windows screen resolution to setup the three screens in an extended mode. You should now be able to change between all 3.
This works great; it even fixed my Rainmeter positioning issue. :) The only problem I have, is that when trying to set up Computer Only, my computer won't let the center monitor (monitor 3) be the enabled one. It always wants to enable the left monitor (monitor 1), and if I change it, either in CCC or Windows, it reverts itself back next time I choose Computer Only.