Check that your computer meets the minimum hardware requirements for running Aero:
1. 1-gigahertz (GHz) 32-bit (x86) or 64-bit (x64) processor
2. 1 gigabyte (GB) of random access memory (RAM)
3. 128-megabyte (MB) graphics card
4. Aero also requires a DirectX 9 class graphics processor that supports a Windows Display Driver Model Driver, Pixel Shader 2.0 in hardware, and 32 bits per pixel.
with a software aero enabler i feel don remem now had blogged it also u can enable aero on a vista basic or win 7 basic which doesnt check for hardware requirements