Computer with Windows 10 - cannot sign into windows

Hello Coleen,

Thank you for contacting Microsoft Community.

We regret the inconvenience you have experienced. 

What is the make and model your device? (I.e. Exact Model)  

Do you see any error message on startup screen? 

Does it responds when you press BIOS setup keys? Like F2, F10, ESC, or DEL key to begin the BIOS Setup

If yes for the last question, then let us try to repair your computer by creating a Windows 10 Bootable media(I.e. USB or DVD) using Media Creation Tool.  If you already had a Windows 10 Bootable media, then ensure that that bootable media should be the same version, which is installed on your PC. If not, use some other PC connected to Internet for creating a Bootable media. Once you're ready with Bootable Media, follow the below mentioned steps.

1. Insert the Windows installation disc in the disc drive or connect USB media, and then start the computer.
2. Press a key when the message Press any key to boot from CD or DVD appears.
   If your PC does not detect the media automatically
   1. During the restart process, read the screen for any instructions that explain how to interrupt normal startup and enter the basic input/output system (BIOS) setup utility. Most PCs use the F2, F10, ESC, or DEL key to begin the BIOS Setup.
   2. Look for a tab in the BIOS Setup Utility that is labeled Boot Order, Boot Options, or Boot. Following the directions on the screen, use the arrow keys to go to the Boot Order, then press Enter.
   3. Locate the CD, DVD, or USB flash drive (this might be called Removable Device) in the Boot list. Following the directions on the screen, use the arrow keys to move the drive up so that it appears first in the Boot list. Press Enter. The boot order sequence is now changed to boot from the CD, DVD, or USB flash drive.
   4. Press F10 to save your changes and to exit the BIOS Setup Utility. Select Yes in the confirmation window. The PC will restart. Allow the PC to restart normally. The scan will take a few minutes and remove any malware that may be infecting your computer.
3. Select a language, a time, a currency, a keyboard or another input method, and then click Next.
4. Click Repair your computer.
5. Click the operating system that you want to repair, and then click Next.
6. On the Choose an option screen, select Troubleshoot. Select Advanced Options >Startup Repair
7. If it doesn't fix the issue then go to Command Prompt under Advanced Options.
8. Type Bootrec /RebuildBcd, and then press ENTER.

You can also go with System Restore option under Advanced Options and follow with onscreen instruction to restore your computer to earlier point of time. If problem still persist, then select Reset this PC with Keep my files option. While performing reset ensure to select Keep my files. It will do the following,

• Reinstalls Windows 10 and keeps your personal files.

• Removes apps and drivers you installed.

• Removes changes you made to settings.

• Removes any apps your PC manufacturer installed. (If your PC came with Windows 10, apps from your PC manufacturer will be reinstalled.)

Warning:

• Be careful when changing BIOS settings. The BIOS interface is designed for advanced users, and it's possible to change a setting that could prevent your computer from starting correctly.

• Updating BIOS should only be done if necessary (to solve a compatibility problem, for example). It can be a complicated process, and if an error occurs, your computer could be rendered inoperable. Be sure to follow the manufacturer's instructions exactly.

Keep us posted if you require any further assistance.