Hi, I have Mac with Snow Leopard and was trying to purchase Lion , so I can move to I cloud, when trying to buy the app I get a message that a minimum 2gb of memory is required. I went check the hard disck info and it says available memory 20gb :-(

Hard drive space, Storage, is completely different from Memory, RAM.

You need 2 GBs of RAM (Memory).

Apple Logo, left hand side of the menu bar, About this Mac. It should be right there. If not then More Info, Sys Info.

But it would seem you don't have 2GBs installed and more then likely both RAM slots are already filed. So you just need to buy more RAM in a pair. That could be 2 1GBs chips or if your Mac can have more then that then 2 2 GB chips or 2 4GB chips.

Get your model # and go to Crucial.com and use their memory search to find out how much your Mac can have installed and the price for it. I suggest you install as much as it can take. Cost is very low on RAM these days.

Apple menu (top left of screen) - About This Mac.

Incidentally, 20GB of hard drive space is actually very low, and I would look at ways to purge unwanted files, or even think about installing a larger hard drive.

Additionally, if you have a Macbook 2,1, as your profile declares, you should be able to run Lion OK (provided you have enough RAM), but you will not be able to run Mountain Lion when it comes out later in the month.

Matt