Alright. Well going by the assumption that it's Windows 8 or 8.1 it gets a bit harder to access internal options if the 0 key isn't working (that was the number zero, not O, just to make sure). Microsoft began to address complaints that previous versions of Windows could take a while to boot, and part of the speedup resulted in making it harder to get to startup options. Windows 10 tweaks this by automatically entering a problem solving mode after three failed boots.
In windows 7 you could press F8 to access some troubleshooting options. Technically you still can in 8.x but the window to get in before Windows takes over is much smaller. Before moving on it's worthwhile to try F8 (or holding down SHIFT while pressing F8) on bootup a few times. Just keep pressing it repeatedly until you either get to a different menu, or just recycle again.
If F8 does work, one of it's options should bring up the built in recovery mode (if that's not just broken too): you may see an option "repair this PC" in the menu.