Roslyn,
Without knowing what failed and how, the safest fix is to use the downloadable recovery image from https://support.microsoft.com/en-us/surfacereco... - you will need a 16GB USB Stick, formatted FAT32. Unzip/extract the recovery zip to the formatted USB stick and then
To reset your Surface from a USB recovery drive:
Step 1: Make sure your Surface is turned off and plugged in.
Step 2: Insert the USB recovery drive into the USB port on your Surface.
Step 3: Press and hold the volume-down button while you press and release the power button on your Surface.
Step 4: When the Surface logo appears, release the volume button.
Step 5: When prompted, select the language and keyboard layout you want.
Step 6: Select Troubleshoot > Reset your PC.
If prompted for a recovery key, select Skip this drive at the bottom of the screen.
Step 7: Select the target operating system you wish to reset. This refers to the current operating system installed on your Surface.
Step 8: Select Yes, repartition the drives, and on the next page, select Next.
Step 9: Choose Just remove my files s.
Step 10: Select Reset.
Surface restarts and the Surface logo displays while the reset process continues (this can take a while).
You will, unfortunately, lose any local files or data stored on the Surface (but if you are using the default storage, docs, pictures, etc. would be saved to OneDrive) and you will need to reinstall apps and programs.
Sorry you are having issues. I hope that reimaging gets you up and running. If this was of assistance, please DO mark as Answer.