I uses a 32 bit windows.7 . I swap the original single 2gb 1066 mhz to a single 4gb 1600 mhz ram stick (both are ddr3) . but after it is installed , the computer restarted automactically after the "starting windows" pops up . but if i put back the original ram with the new once , it cqn actually run and shows that i have 6 gb of ram (2.9 gb useable) . but i only want the 4 gb ram . whats wrong with it ?