What should I do if the background of Win8 system suddenly turns black?

1. Press WIN+R to bring up the running window, then type regedit and click OK to open the registry editor.
2, then on the registry, expand the HKEY_CURRENT_USERControl PanelDesktop item, then find the LogPixels key value in the right pane, and then delete it.
3. If you do not find the LogPixels value in the above window, you can right click on the win8 system and select Personalize ——“Show”——Resize all items and apply save After that, you can find the LogPixels value under HKEY_CURRENT_USERControl PanelDesktop and delete it.
4, finally restart the win8 system, or set the system background image.