Hi,
When you're in that white screen press CTRL, ALT and DEL again and select Task Manager. Once it's open on the top right corner click on File then select "Run New Task" and type in "explorer.exe" and press Enter. It should bring back your normal desktop screen. If that doesn't work open Task Manager again and go to Startup tab and disable all the startup items listed in there, close Task Manager and reboot the laptop again. Lastly is to perform a System Restore in Safe Mode. To load Safe Mode, while the laptop is booting up keep on tapping F8 until you see Advanced Boot Option and select Safe Mode and press Enter. Once Safe Mode is load just do the System Restore put it back to an earlier date before the issue started happening.