Question: how to change hkcu for all users?
Answer: Find the key/s you want under HKCU in regedit, export it/them. Now right click on the HKEY_USERS key and select load hive. ...  in your exported reg file replace all instances of [HKEY_CURRENT_USER\ with [HKEY_USERS\NAMEHERE\ (or whatever you named your hive) and save the file. double click the reg file to merge it.