So i downloaded some games on my ps3 hard drive and they are hardly of 12 gb yet it keeps showing i have 15gb out of 80 gb free. Please help.
Are you saying you've only downloaded 12 GB but your PS3 is saying you have 15 GB free? It's not really clear. What else do you have on your PS3? Installed disc-games? Saves? Movies? Music? It's also possible you have corrupt files that can be cleared out if you restore the file system and database. Also, keep in mind that the actual available space is about 64 GB.
Is this a brand new system? Unless you've never played a disc game, I find it unlikely that you wouldn't have anything installed (unless of course you deleted it all). Check the game data utility and see how much space is taken up there. But like I said, it's also possible something is corrupt with your HDD. You might even want to reformat the drive if you can't find any files taking up that space.