Hi. Currently the way to disable hibernation is:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Power]
"HiberbootEnabled"=dword:00000000

which is OK, but it keeps and locks hiberfil.sys image file in C:\ root folder from deletion which grows as large as 40% of RAM.

Using this method

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power]
"HibernateEnabled"=dword:00000000

disables Fast boot as well but also releases hiberfil.sys to be deleted (although you have to do it manually after enabling to Show system files). As a side effect it also removes Hibernate option from Windows power menu which may be beneficial or detrimental depending wether you use it manually or not.