My laptop FROZE so I shut it down by holding the power button, but not it won't start.  It reboots itself and then shuts down repeatedly.  What did I do wrong and how can I fixed it?It sounds like either your charger or battery is bad.  Is this happening while it is plugged in to the charger?  If so, it is probably the charger.  If not, probably the battery.

Hoop2077Oh shoot...  I missed the part about it freezing.  Please disregard my last post.

Sorry,
Hoop2077This is what the error says:

A problem has been detected and windows have been shut down to prevent damage to your computer.

UNMOUNTABLE_BOOT_VOLUME

If this is the first time you’ve seen this error screen restart your computer.  If the screen appears again, follow these steps:

If problems continue, disable or remove any newly installed hardware or software.  Disable BIOS memory such as caching or shadowing.  Checked to make sure any new hardware or software is properly installed.  If this a new installation, ASK your hardware or software manufacturer for any window updates you MIGHT need.

If you need to use safe MODE to remove or disable components, restart your computer, press F8 to select Advanced Startup Options, and then select Safe Mode.

Technical Information:
*** STOP: 0x000000ED (0x84F919A0, 0xC0000015, 0x00000000, 0x00000000)

I tried pressing F8 and clicking on the safe mode, but it does nothing.
Specifics on the hardware, age, etc. could be helpful, don't you think?

You need to start by seeing if the hard drive is recognized correctly in the BIOS and running thefree diagnostics from the appropriate hard drive maker's site. If you don't know use SeaTools at www.seagate.comWhat kind of surface is the laptop placed on and can you hear the fan spanning? UNMOUNTABLE_BOOT_VOLUME seems to be an issue with the Hard Disk Drive.
Run a Test on the HDD in BIos ( If available ) - find out Results.
Reseat HDD and Try to boot  - find out Results
If possible, insert another HDD into this computer or visa versa - Find out Results...

Let me know what happens then...This, of course, was previously suggested. We are waiting for the original poster to return.Think about it - is your backup up-to-date or do you have critical files on the hdd which might be failing?   The most important thing on your pc is your IRREPLACEABLE files - should you get into file recovery mode before attempting to resuscitate the drive?

See here..

Good luck