My MBP will not startup properly!
Blue screen is indicating a user level problem loading your specific settings.

You can overcome this in two ways:


boot in safe mode and log in and make a new admin account - set that new account to auto-log in or disable auto log in.
boot in single user mode, run fsck as directed, then mount the filesystem and delete /var/db/.AppleSetupDone and type exit


At that point, you can let the setup assistant create a new temporary admin (and temp_admin might be a good user name to choose to avoid matching an existing user name) so you can look at the system logs and clean up whatever user preference or program is interrupting the boot cycle.

If as you mentioned, you really can't boot at all off that drive, then you have bigger problems and need to bring a new OS on an external drive (or perhaps SD card) to the mix or seek help from someone that can back up your files or assist in reinstalling the OS from an external source.