RE: XPS 15 screen becomes white
Thank you for trying the steps mentioned previously and as you heard the beep sound the Diagnostics were running in the background and it looks like issue with the LCD screen. Please try connecting an external monitor to your computer and check if it works fine there and if the External monitor works fine then it might be the LCD screen's gone bad and needs replacement so please send us the Service tag of your computer on a private message, To send a private message, click on my user name and select send a Private Message and provide your service tag and contact information (as mentioned below) so that I may access your system records.
System Service Tag No:
Registered System Owner's Name:
Please provide these information if the error still persists with your computer and we’ll see what best can be done.