Dont you need to have a 64-bit processor to support more than 3gb of RAM? I forgot about this and installed 4gb on my laptop and am almost positive thats the issue you are having. There is no reason to format your computer, that definitely wont change any issues with how much RAM is available, but if you really want to you could do it to help clean up some of the junk on your HDD. You could also have a 64bit processor and be running a 32bit operating system like Windows XP and if that is the case then upgrading to 64bit windows 7 should fix it. Look up your laptop model number and see if you can tell if the processor is 32- or 64-bit, if you cant then post here and somebody should be able to