Jerry, if you first delete PW's campaign folder out of the RoF directory, then install a fresh copy of a 10.3 download, then there should be no old campaigns.
Also, click on the Low setting, do not edit the config file (other than the line that finds the mission results), and your problems should be solved.
BTW, System specs?
4x2.66 GHz Xeons, XFX 4870 1 GB, 11 GB DDR2 RAM, Win7 Pro x64, 120 GB OCZ Vertex2 (MLC, Sandforce)
26" VIZIO 1920x1200, Logitech FF 3D Pro, CH pedals, Track IR4