Ok, so it's been awhile since I tried this but I've only got 512MB of ram in my system. I tried to install another stick, also 512MB and the same speed, only to find my PC wouldn't post. I entered the BIOS and fiddled with some settings and got nothing. I could use either stick alone and get a post but together my sys wouldn't post. I even took my comp up to PC Club and they didn't know what the deal was. They said I'd have to just buy 2 matching sticks then they'd prolly work. Well I'm reluctant to do that so I just said I'd pass. They literally had no suggestions other then buying 2 sticks. So I got a refund on the one I bought. Anyone know why this would be an issue? I thought as long as the ram was the same speed and size, adding another stick was a mindless task. Apparently not.