Hi all, I am an average PC guy just learning to operate a Mac. This is a beautiful piece of engineering even if rather old. I just want to be able to update Chrome and also load printer drivers for my brother printers.The model number is 8,1 and it has 2 GB on board. I tried downloading -- Install Mac OS X. DMG -- When I clicked open it told me it was not recognizable. there is only about 2 gigabytes in the file so maybe it's incomplete?? Will I be able to upgrade to a more contemporary operating system? Also, I have an external hard drive which has recently backed up.