Windows 7 Aero

I have a Dell D820, a few weeks ago i could display Aero, however i have just noticed last night it hasnt been displaying i am not to sure why its just stopped so i troubleshooted, my G-cards fine, and when i went into display propeties it had a option of going to troublesoot did that and it came up with a service called Windows Live Mesh i looked everywhere for this service i cannot find it?, and i like the look of aero…