Force Enable Aero in Windows 7
1. Click on Start and type regedit at run

2. Now Navigate to the following registry key:
HKEY_CURRENT_USER\Software\Microsoft\Windows\DWM

3. In the right details pane, create following Three DWORD (32-bit value) entry
UseMachineCheck, and set its value to 0.
Blur, and set its value to 0.
Animations, and set its value to 0.

4. Close Regedit

5. Click on Start and type CMD with administrative Priviliges

6. Now type following command
Net Stop uxsms
Net Start uxsms
Above command will stop and start Desktop Window Manager Session Manager.

7. Now you can turn on Aero by right clicking on desktop-> Personalize -> Select Windows Colors
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Source: http://answers.microsoft.com/en-us/windows...12-c96130038d5c