OK Twiz...and injuneer1 (welcome to PCX by the way

)
This is the definitive article:
Windows Vista or Windows Server 2003 may report less memory than you expect
Hate to say I told you so
Oh yeah...and if you're not dual-booting (I am) you'll need to follow the instructions in the article linked in this post to enable PAE for Vista. I didn't know that.