im not sure if this is correct, but my computer is only aloud to have 256 RAM max. I have a compaq presario...I tried to bump it up to 512 and it wouldnt work. I also looked online at compaq.com for a program to flash my bios to make it work. Couldnt find one. As for a hard drive, can I put another HD in here if I have only 256 RAM?