Having a little problem with my Gateway pc. I have model #gm4019e with c51gu01 motherboard. Upgrading from 2 x 512mb pc3200 chips. Would like to add 2 x 1024mb chips. Have tried different arrangements but neither the new or old memory chips will work if they are in dimm 2 and/or 4. when memory is in dimm slots 2 or 4, the computer opening screen freezes with faint vertical lines show as video disturbance. can't go into cmos from there. Computer sounds a long beep when I try to start up with with a memory stick in dimm 2 slot. The existing 512's were in dimm1 slot and dimm3 slot and the 1gb upgrades work in those slots but windows only recognizes 1.87 gb. I would like to use all 4 sticks for a total of 3 gb but nothing will work in dimm 2&4 slots.