If your power went out and came back on very quickly and/or went off and on sereral times very quickly it probably toasted your boot drive. I had that happen on a brand new build with a brand new SATA drive. I had just finished loading the OS and took a short break beforfe starting to install all my other software.
Also note that SSD's have a problem with unexpected power outages that can cause drive corruption.
The answer for the future is to use an uninterruptible power supply or UPS. If you have a lot of power outages also set your BIOS power options so that when the power goes off unexpectedly it doesn't automatically restart - it just stays off until you manually restart it.