Wait and check
Sometimes Windows takes 30–60 seconds to render the desktop after login, especially after updates. Give it a full minute.
Explorer.exe restart
Press Ctrl+Alt+Del → Task Manager → File → Run new task → type explorer.exe → OK. This restarts the shell and usually brings the desktop back.
Startup app conflict
Boot into Safe Mode. If the desktop appears normally, a startup program is causing the black screen in normal mode. Disable startup programs one by one via Task Manager → Startup.
Display driver issue
In Safe Mode: DDU → uninstall GPU drivers → reboot → reinstall latest driver from manufacturer site.
Shell registry check
Regedit → HKLMSOFTWAREMicrosoftWindows NTCurrentVersionWinlogon. Confirm the Shell value is explorer.exe. Malware sometimes changes this value to a malicious executable.