ive just upgraded my RAM by installing 1gb. i already had 512mb installed ASWELL. when i installed the 1bg it only read 1 bg, not 1bg and 512mb. why is this?you probably had to remove the old RAM (probably 2 256 STICKS) to get the new RAM in.oh okay.. so are you saying that when i put in the 1gb stick in the computer, i had to remove the 512mb stick then put it in again so that the computer reads both sticks?What's the make/model of the motherboard? It MAY only recognize a maximum of 1 GB.Motherboard manufacturer's name: ECS RC415ST-HM
Did you look in CMOS to see if ALL ram is recognized by the motherboard?If the new RAM is high density and the old RAM is low density it will cause the computer to only recognize the high density (I think).Is the new RAM PC3200 ? ?

If not it will not work.....
Not all RAM is the same.

Quote

* Single-channel memory architecture
* 2 x 240-pin DIMM sockets
* SUPPORTS PC2-3200 (400 MHz), PC-4200 (533 MHz) DDR2 DIMMs
* non-ECC memory only, unbuffered
* Maximum HP/Compaq approved memory is 2 GB

Motherboard manufacturer's name: ECS RC415ST-HM

That link has the identical specs i posted...

Oooops....sorry...forgot where i was at the moment.....