How can I get the Aero Glass without installing a LDDM driver
To run Aero Glass, your graphics card must have a Longhorn Display Driver Model (LDDM). NVIDIA offers a Vista Beta 1 LDDM driver, and ATI also has LDDM drivers available. To get the full Vista experience, the graphics card needs a lot of memory (64MB minimum, 128MB recommended) and must support the complete DirectX 9 API.
rear what was posted above "your graphics card must have a Longhorn Display Driver Model (LDDM)." which means no LDDM = no aero.