It sounds like your user profile may be corrupted. You could try CTRL+ALT+DEL and open task manager from the security prompt if it opens. In task manager click File -> Run New Task. Type Explorer.exe into the dialog box and hit OK, the desktop should launch.
If that doesn't work then I would try to get into safe mode from the log in screen:
- "Get to safe mode from the Windows sign-in screen:
- On the Windows sign-in screen, press and hold the Shift key while you select Power Circle with line Power icon > Restart.
- After your PC restarts to the Choose an option screen, select Troubleshoot > Advanced options > Startup Settings > Restart.
- After your PC restarts again, select the startup setting you want to use.
- When you're done, exit safe mode by restarting your PC. If that doesn't work:
- Press the Windows logo key Windows logo Start button + R.
- Type msconfig in the Open box and then select OK.
- Select the Boot tab.
- Under Book options, clear the Safe boot checkbox."