How to set the number of switching windows displayed in win7 computer?

How to set the number of switching windows displayed in win7 computer? Below, let Xiaobian tell everyone, how to operate it!
1. First, we need to use the shortcut key combination of win+r to open the running window. In the open running window, we enter regedit and click Enter, so you can open the registry editor window of your computer.

2. Open the Registry Editor window, click to expand our turn HKEY_CURRENT_USER Control Panel Desktop menu on the left, and then we move the mouse to the right window, where you can find the name of The option for "CoolSwitchColumns" is gone.
3. Let's double-click to open the CoolSwitchColumns option, and then in the pop-up window, we will delete the default value data, and then reset it to the number of switching windows you want.