I recently got a 2009 24 inch imac from someone. It was very slow so I decided to repair the disc and wipe the thing clean and start from scratch. Unfortunately It wouldn't allow me to install the Os because I didn't have enough ram. I checked system profiler and it says I have 512 mb of memory but the memory section lists 2 ( 2 gb DDR@ SDRAM cards that are ok). Whats causing this? Edit: I'm booting from OS disc now the whole hard drive is wiped clean.