let's make this simple My iMac did not come with Snow Leopard. It is a 24" late 2008. I bought Snow Leopard from Apple and installed it on the Mac and everything was fine until my HD failed about six months later. I want my mouse to work properly (neither the original keyboard mouse nor my wireless work properly any longer). Is there any trick to just pulling the Snow Leopard disc out and slipping it in for a reinstall? Is it that simple or will I lose anything such as software added. Thx.