I have an i1Display pro and have used it with the iProfiler software on several monitors with no problems . Recently I purchased a NEC PA271w. I am using dual monitors (Samsung 243T with the NEC). When I start the calibration, the NEC moniter changes to a very magenta cast whether I am calibrating the NEC or Samsung; the Samsung retains its normal color. I have been able to restore the correct color in the NEC only through Windows system restore. I am using a Dell XPS 435 desktop, W7 64 bit, Radeon 4xxx. Any advice? Thanks.