Missing Memory In Windows 7

I need a little help trying to diagnose my daughters computer problem while I'm deployed to Afghanistan. She just recently has windows 7 home premium 64 bit installed. It's been working great for over a month now, but yesterday she said she tried to install a game and she got an error saying she doesn't have enough memory. I had her bring up the system box in control panel, and it showed her score of 5.2 but next to memory installed it was empty. now we know memory is installed because she's able to use the computer. I know for a fact there's 2 GB of memory. I'm sure it's just a windows thing, but I'm unfamiliar with windows 7. Please help with any ideas as to what I can have her look at.