1) Turn off phone.
2) Press and hold Volume-Down button. Or Volume-Up. I forget which. Down I think.
3) While holding Volume button, hold Power button.
Phone will now enter bootloader. At the top of the screen will be some information, among the info is HBOOT and version number.
If the power button simply turns on the phone, rather quickly, regardless of which Volume button you hold down, you have fastboot enabled. To disable:
1) Settings, Power, Fast boot (uncheck it).
Hastily spouted for your befuddlement