How do I fix a white screen after login?
If your PC goes white on the Sign in screen or after you hit the Sign in button, try using the Ctrl + Alt + Delete key sequence to open the Windows Security Options page. If the page opens, go to the bottom-right corner, click the Power icon, and then click on Restart.
Why is my laptop screen white when I log in?
The 'laptop white screen' issue may be caused by a virus attack. So run your antivirus software to do a security scan and clear existed viruses or malware. Be sure that your anti-virus software has been updated to the latest version.