I have done everything I know of to fix this problem except replacing the CPU and MB. It doesn't matter what OS I install, this Compaq Presario 4880 locks up everytime I try to do 2 or more things(multitasking problem???Replaced RAM, didn't fix it). Could the CPU be causing this? What other things could be happening here. PLease help. Email me if you have any suggestions or need more info. Jerry