my home screen is black and white

This usually points to a Windows display color setting rather than a startup problem, since the startup screen is normal and the desktop changes after sign-in. The printer also printing in black and white can happen if black-and-white printing is selected in the print settings.

Try these steps in order:

1. Check Color Filters
   • Press Windows logo key + U.
   • Select Color filters.
   • Turn Color filters Off.
   • If it is already on, turn it off and check whether color returns.
2. Check Contrast Themes
   • Open Settings.
   • Go to Accessibility > Contrast themes.
   • If any contrast theme is enabled, set it to None.
3. Check Windows color mode
   • Open Settings.
   • Go to Personalization > Colors.
   • Make sure Choose your mode is not forcing a dark or unusual theme if the display looks wrong.
   • If needed, switch to Light and test.
4. If the screen still stays grayscale after those settings are off
   • Open Device Manager.
   • Expand Display adapters.
   • Uninstall the graphics card device.
   • Restart Windows.
   • This forces Windows to reload the display driver.
5. If the problem started after Windows updates or the driver still looks wrong
   • Open Settings.
   • Go to System > Recovery.
   • In Fix problems with Windows Updates, select Reinstall now.
   • This does not affect files, settings, or installed apps.

For the printer printing in black and white:

• In Word, go to File > Print.
• Under Printer, select Printer Properties.
• Check whether the printer is set to Black & white or Grayscale, and change it to color if available.
• Printer options depend on the printer model.

References:

• Use color and contrast for accessibility in Microsoft 365
• I have lost all color in Windows on my Acer Laptop - Microsoft Q&A
• Screen turns black background with white text. - Microsoft Q&A
• Print in black and white