Most interactive modifications to the Registry are made in one of two ways: you can change the value of an existing key or you can add a new key, including the key name, data type, and value.
To enter a key value, just double click on the key and dialog window will be displayed with the current value. Enter the new value and press the OK button.
To add a new key, select the Add command from the Edit menu. Enter the name of the new key, the data type, and, finally, the key value, and then press the OK button. Pressing Cancel will let you undo the current change. Any change to the Registry can make your system unbootable, so if you have any doubts press Cancel and leave the Registry unchanged.