Registry data types are just labels

If you poke around the Registry Editor enough, you might find some values of the Data column that say something like "invalid DWORD (32-bit) value." This happens when the data held in that value is not the right length for the supposed data type. DWORDs should be 4 bytes long, but there's nothing stopping them from being anything else. The function responsible for setting values, RegSetValueEx, takes a data length and pointer to the data. To view and edit these entries of unusual length, double-click them in the Registry Editor to open the binary data editing window.