Boot only when connected to a Pc Is possible to set my Android(Asus Zenfone 2) to only boot with it's connected to a specific computer via usb.

No problem if root is needed.
No, there is no trivial way to do this. You would have to write a custom bootloader for your phone.

If your intention is to protect your data, a viable option would be to use full disk encryption, which does not even require root.