According to Microsoft, there are two methods to fix a C:/Windows/system32/cmd.exe error: boot the computer into safe mode, then troubleshoot to determine the cause of the issue, or perform a system restore. C:/Windows/system32/cmd.exe errors are frequently caused by misconfigured system files.
To boot a computer into safe mode, all external hard drives must be removed before restarting the computer. Once the computer boots back up, press and hold the F8 key to access safe mode.
To perform a clean boot in Windows 8, use the search option and type "msconfig". On the Services tab, check "Hide All Microsoft Services," and select "Disable All". Then select "Open Task Manager" in the Startup tab. Select "Disable". Apply the changes, and restart the computer.