A Windows PC that hasn’t been booted for months may get a black or blue error screen:

A component of your operating system has expired winload.efi

You will need to update to the latest version of Windows, after backing up your files. In BIOS/UEFI, set the date to about the time your PC last worked. If you’re not sure, set the date roughly 6-12 months into the past. Reboot and Windows should start, but will note an expired version of Windows. Windows will set the correct date automatically. Copy off all your data to an external drive. Don’t reboot! Do the “force upgrade” below.

If this fails, you can recover non-encrypted (non-Bitlocker) data by copying your data off to USB or network drive with an Ubuntu live USB stick or pull the hard drive and copy files.

Force upgrade with the Windows Update Assistant and run on that PC.