Please help me, I'm a noob so please keep things simplified. My parents have a 8.1 iMac (2.4ghz) which is only running on 1gb and I'm upgrading their computer as a gift. I decided to go with 4gb from Cosair but when I ordered it online I did not realize when I ordered it that I got single stick, not a kit. Should I return the memory and get the 2x2gb instead? If not, should I remove the other stick in there when I install the 4gb, or use both for a total 5gb? It looks like it is running 1 1gb of ram now as opposed .5x.5. Any help appreciated. Would rather get it right after the holidays then mess it up now. Thanks!