Windows cannot find 'gpedit'. Make sure you typed the name correctly, and then try again.
If this is the Error Message that you are getting it is because you have only typed in gpedit
You need to type in the full file name gpedit.msc
Here is an extract from the Help file.
Group Policy Management Console
The Group Policy Management Console (GPMC) snap-in provides a single user interface through which to manage Group Policy across an enterprise. GPMC consists of a Microsoft Management Console (MMC) snap-in and a set of scriptable interfaces for managing Group Policy.
You can find the GPMC snap-in in the following location: %windir%\System32\gpedit.msc
Important:
It may be necessary to run MMC with elevated privileges even if your account is in the Computer Administrators group.
To open MMC with elevated privileges, click Start, click All Programs, click Accessories, right-click Command Prompt and then point to Run as administrator. If Windows displays a security message asking your permission to run this program, click Allow. In the command prompt that opens, type mmc.exe to start MMC. In the console tree of MMC, click File, click Add/Remove Snap-in, and then select Group Policy Object Editor and Group Policy Management and click Add.
Group Policy Object Editor
Group Policy Object Editor is an MMC snap-in that you can use to edit Group Policy objects (GPOs). After GPMC is installed, you can open Group Policy Object Editor from GPMC.
You can find this MMC snap-in in the following location: %windir%\System32\gpedit.msc
To open the local Group Policy Object Editor, click Start, click Run, and then type gpedit.msc.