Disable F8 option in Windows 7 and Safe mode in Windows 10

Disable F8 option in Windows 7 :

• Run cmd as administrator and type this command :   

          bcdedit /set {bootmgr} displaybootmenu no

• Then hit enter, You're done.

Disable Safe mode in Windows 10

• Open registry editor or regedit
• Navigate to :

         "HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SafeBoot"

• Expand the SafeBoot key and you should see 2 sub keys with the names Minimal and Network. DON’T delete them, but rename both of the keys to something else, for example, Minimal to MinimalX and Network to NetworkX.
• To rename those sub keys you need to change the owner from system to your current account login, eg: administrator or admin. By right clicking in the sub key and choose permissions then click advance, then click change on owner section at the top.
• Then type everyone or administrator or your current login in the "Enter the object name to select" then click "Check Names". Click ok then checklist "Replace all child object permission entries with inheritable permission entries from this object" and then click apply.
• Then checklist Full Control and Read for administrator or your current account in Allow section. Then hit apply and ok.