Aero not working on Windows 7

Aero was a nice visual addition in Vista which also exists in Windows 7. It's not just eye candy, the Alt-Tab preview and the aero peek on the task bar are incredibly useful. A common recurring problem is when it stops working for no apparent reason. Microsoft even has a little automated utility to try to help you fix it.

When this happened to me, I spent a little time searching, and found the above utility. It did nothing and claimed that my video card (a Radeon 7970), which used to display Aero perfectly, isn't capable of supporting Aero.

Here's what I tried:

• Many reboots: didn't help
• Updated the graphics drivers: didn't help. The repair utility still claimed that my graphics card doesn't support Aero
• Installed all updated, which I was behind on: This didn't help either
• Tried killing all running process that I could. No go.
• Uninstalled a few applications I had installed in the past 2 days, still no go

Finally I remembered installing the IE 10 preview, in the past 2 days, but it does not show in the add remove programs - it shows under installed updates. I uninstalled IE 10, but it still didn't work. So, I started looking at other updates. I hadn't installed any updates the day I installed IE 10, but I found 3. Installed each one and rebooted each time. The first 2 did nothing, but finally after the last uninstall and reboot, Aero started working again.

I should have made note of the KB update number(s), but at this point I was pretty frustrated, thinking I'd have to restore a drive image. If any one knows the KB numbers of the updates installed with the IE 10 preview, please let me know.

Summary: IE 10 preview and associated updates can cause Aero to stop working.

Edit 2012-11-19: Thanks, Dean for the KB update number: KB2670838.