Question MacBook Pro not booting

[exonsx]

I have a MacBook Pro mid 2012, so I installed Windows through boot camp without checking the install latest drivers so when I booted into Windows I had no drivers after downloading them from Apple's website I installed the boot camp setup and it asked me to restart now it's stuck at the blue screen and my mac partition is also gone

 

[jojesa]

Installing Windows does not overwrite the Mac OS partition.
Power on your Macbook, and immediately hold down the Option key.
Release the Option key when the Startup Manager window appears.
Select the macOS press Return key to boot from the Mac OS.

Use the Boot Camp Assistant to remove the Windows partition

I suggest you try to install Windows again but this time have all driver on a USB flash drive...make sure the driver are uncompressed (unzipped).