I had the same problem when I tried to install windows using my OCZ reaper 2x1 kit; it kept freezing up when installing. I used my mushkin 2x2 1600 kit to install windows and am still using them now, theyv e modestly overclocked, and have provided my system with the stabilikty i needed to get to 4ghz. However the OCZ kit was also fine once windows was installed and achieved the same overclocks; it seemed the problem was with installing windows.