HatchyDub :
If it's relevant, every now and then the computer freezes and says "AMD display driver has stopped working", it sometimes recovers and sometimes freezes until restart
Yes, that is definitely not right. Along with the display driver giving you issues, I'd wonder if the card was defective.
1) Did this just start happening, or has it been like this before the driver was installed?
2) How are you connected between card and monitor?
Try uninstalling the AMD catalyst pkg, everything associated with it. Reboot, let Win7 install its own driver, then reboot to BIOS and see if it still is the same.