now what you need to do is go into your display properties, and the section where you would set the system colors... select advanced properties, and the you have a choice of windows classic, vista basic, or aero... you want to select aero
the way to tell if Aero is already running is to look at your title bars, if they are transparent you are running aero, and that's not your problem, if they aren't transparent you've found your problem...
let us know how it's going...