I heard that Windows Vista itself will sometimes decide to disable Aero. What’s up with that?
. In general, Vista will disable Aero if it determines that it needs to improve performance, recover from a technical issue, or (in the case of laptops in power-saving mode) reduce demands on your battery. According to Microsoft, Java apps are the most common trigger for disabling Aero. Remotely viewing or sharing another machine’s desktop can cause Vista to disable Aero, too, and Vista disables Aero when presenting a User Account Control (UAC) elevation prompt.