I unistalled the drivers and the names of the monitors changed to Display device on: Mobile PC Display for the mini display, and then VGA for the other one.
As I haven't used a 3 screen setup on AMD I can't really comment further besides give basic troubleshooting tips. My advise, is if it worked before, the only thing I would continue trying is uninstall, Driver Sweeper all AMD drivers, start from scratch with the exact same plug in config you had before.
I believe he is using passive adapters. The adapters should work at that resolution though. I had something similar happen to mine and I think it was just a matter of going into the CCC and disabling the other monitors, then setting up the extended desktop again. It's been a while since it happened.
Did you do like I said previously by using Driver Sweeper to get rid of ALL AMD drivers and software? Reinstalling Windows does essentially the exact same thing.
So you:
Uninstalled all AMD software,
Used Driver Sweeper to remove any lingering drivers,
Rebooted,
Downloaded latest AMD Catalyst drivers from the site,
Installed and rebooted,
and now it will only use one screen?
I'm also assuming you have .net 4.0 installed to utilize CCC.