I have a acer 3100 desktop w/amd athlon 5600 64x2 with 3gb ram. installed win 7 premium 64 bit version with no problems. tried to add 1gb 5600 of ram to total the mem to 4gb total. now system will not boot to normal windows. but will boot in safe mode. i removed the ram and everything went back to normal. the ram was matched to the others,but computer will not accept it. need help resolving this issue and if possible would like to know if i could bump the ram even more.