Re: my dell latitude e6420 screen goes blank when it has to boot
Restart the system. Press F2 for BIOS. Let me know if the hard drive is detected in the BIOS.
Did you connect any external display lately?
Connect an external display and check if the display comes on it.
Also, try pressing F12 on the Dell Logo and check if the system boots to One Time Boot Menu. If yes, highlight diagnostics and hit enter.
Thanks & Regards