Hello,

I just bought a new laptop and also a new 2 GB Kingstons 5300 SODIMM 667 mHz RAM (the original memory was 1 GB... had to upgrade because Vista eats so much memory.) I bought two of these 2 GB RAMs. When I finished installing my two 2-GB RAM, the BIOS recognizes as that there is 4 GB of RAM available but Vista only recognizes to only to be 3 GB available. What happened to that extra 1 GB of RAM that is suppose to be available? Shouldn't Vista recognize 4 GB of RAM instead of 3 GB? Can you help me out to see what's the problem? Thanks. I appreciate it.Basically your problem is that 32 bit Vista can't utilize 4 gb of RAM. This article describes it better than I can.
http://www.crucial.com/kb/answer.aspx?qid=4251

This is a limitation of 32 bit computer architecture. The only solution is to switch 64 bit Vista instead. (Switching to 64 is not hassle free though.)It will still use most of it...i'd say if the system is running fine don't worry about the way your RAM is being reported...
And Deerpark is correct...migrating to 64Bit Vista has had many a person lose PLENTY of sleep.