I recently spent a large amount of money on a couple of toys: an Apple MacBook Pro and a Windows Vista-based notebook computer. Each one runs the latest version of its operating system and each has four gigabytes of random access memory (Ram). Why does my Mac give me access to all the memory while my Vista machine allows me only 3GB? What has happened to the other gigabyte of Ram? Name and address supplied DQ: The answer to your question has to do with so-called 32-bit and 64-bit computing architecture. Without getting into too much detail, you have a 32-bit version of Vista installed on your machine. The memory limit for such a system is 4GB, but that is for everything in the system, including your graphics card. That means if you have 512 megabytes of video Ram, it will take that amount from your total available Ram. You could install the 64-bit version of Vista, but you may end up creating an entirely different set of problems. Many peripherals are not yet supported in 64-bit computing mode. Do a Google search and you will find a great deal of information about the differences between the 32-bit and 64-bit versions of the Windows Vista operating platform. The Macintosh system does not have this issue. For many years I have stayed away from digital cameras. I always felt film cameras were better. Now, I'm thinking about taking the plunge. I have always been a Canon user, so I am not sure about using another brand, such as Nikon. Canon film cameras are good, but does this mean they also get it right with digital cameras? John, Mid-Levels DQ: This is another one of those questions about which many people will have strong and widely different views. The best thing I can do is point you to a few sites and hope they help you to make your decision. Three good reference sites are www.digitalrev.com , www.dpreview.com and www.steves-digicams.com/hardware_reviews . The most important thing in both traditional film and digital photography - from a technical point of view, at least - will always be the lens. If you have a good lens you are halfway there. (Talent helps, but that's another story.) Both Canon and Nikon have excellent lenses. If you already have a collection of good lenses, you may want to use them with your new digital camera. Alternatively, you may want to take this opportunity to start from scratch.