Hello Barbara, I am Henry and I want to share my insight about your issue.
The screen you are seeing is BitLocker Recovery, a security feature that has locked your drive to protect your data. To get back in, you must find your 48-digit recovery key.
You cannot bypass this screen, but finding the key is usually straightforward. You will need to use another device (like your phone, a tablet, or another computer) to find it.
Here are the action plan you can refer to:
When BitLocker is enabled on most modern computers, the key is automatically saved to your Microsoft account.
- On your phone or another computer, open a web browser.
- Go to the following secure Microsoft link: https://account.microsoft.com/devices/recoverykey (You can also search for "Microsoft BitLocker recovery key" to find this page.)
- Sign in with the same Microsoft account you use to log in to your locked computer.
- You will see a list of one or more recovery keys. Match the Key ID shown on your computer's blue BitLocker screen to the Key ID on the website.
- Carefully type the long 48-digit Recovery Key from the website into your locked computer's screen and press Enter.
What To Do If The Key Isn't There
If you do not find the key in your Microsoft account, think about where else it could have been saved when it was first set up:
- A work or school account? If this is a work computer, your IT department has the key. You must contact them for help.
- A USB flash drive? You may have saved the key to a USB drive. Plug it into the computer and follow the on-screen instructions.
- A printed document? You may have printed the key and stored it in a safe place.
If You Cannot Find the Key
If the recovery key cannot be found, the data on the drive is encrypted and cannot be recovered. This is a security feature, and there is no backdoor.
The only way to use the computer again is to reinstall Windows, which will erase all of your files. You can do this by creating a Windows installation USB drive using another PC and the official Microsoft Media Creation Tool.
Hope one of these works for you. If you find this guidance helpful, you're welcome to click 'Accept Answer'—it helps others find useful solutions too.