Well, i think you may want to install an extra two gigs of ram in Vista if you have any games that are graphic intensive like World in Conflict or Age of Conan, or you just run a lot of programs. My brother and i got out of memory errors all the time when we tried playing those games or had lots of folders or browsers open, but these problems went away after my friend installed an extra two gigs for us . so it seems that more memory is better for Vista. Besides, my IT friend explained to us that adding more ram to run Vista would allow games to run in memory instead of using the hard drive.
Hah
our problem has been solved by my IT friend, hope this would help you too. BTW, Take your time to learn buddy, i am new at this thing too, have fun!