OK, I tried to install memory on my friends computer but it just gives me problems. He has 512MB, and bought another 512MB stick. Separately both of the memory sticks work, but when he tries to install them together it just gives problems. The computer power light just blinks repeatedly, and makes a beeping noise. They are different memory types but I figure that wouldn't matter and it would just run at the slowest speed. Can anyone offer some insight on this.