Linux mint problem with dual monitor setup

[OkamioftheRinnegan]

okay, so i have Linux mint 14 x64 cinnamon dual booted with win7 with dual monitors. i recently installed the proprietary drivers(amd catalyst 12.10) for my amd hd 6570 graphics card and set it for extended displays. the problem is if i boot up linux with both monitors attached, then i am unable to log on. my primary monitor is a black screen with the x mouse cursor. i can move it around, but if i move it towards the side that my other monitor is, then it instantly moves to the other side of the screen. my secondary monitor has the log on screen with the active text field, but i can't type anything into it. any help would be greatly appreciated.

please try to keep any solutions simple. i am new to this