Windows 7: I lost Aero Peek

I lost Aero Peek so how do I get it back. Peak at desktop is grayed out. Taskbar properties Aero Peek check box is grayed out.

Did you change your theme to one that disables aero?

Ask the Internet and it will take you to a group that can answer your question
1.Click on Start menu.
2.Type the following text into the Start Search box: Aero and press enter.
3.Select “Find and fix problems with transparency and other visual effects” from the menu (i.e. control panel).4.An “Aero- Troubleshoot computer Problems” wizard dialog will appear.
5. Click on Next button.
6. The troubleshooting wizard will try to detect any problem by running a series of checks against various components required to make Aero works and running, such as video memory, Desktop Windows Manager (DWM) service, color depth, theme, power settings and etc. At the end of the analysis, the wizard will attempt to fix the issues related to Aero service and restart the Aero feature.