The User Key represents the location of the value in the Windows registry. User keys are generally located under the HKEY_CURRENT_USER hive and affect only the current user.
The System Key represents the location of the value in the Windows registry. System keys are generally located under the HKEY_LOCAL_MACHINE hive and affect the entire system.
The Value Name specifies the name of the registry value that should be created or modified. Value names are not normally case sensitive.
The Data Type specifies the the data format of the value. Typical formats include:
See the Registry Tutorial for further information.
The Value Data specifies the acceptable data the may be written to the value.