Welcome to the Dell Community [NAME]  Remove the Main Battery. Remove Base Cover. Disconnect the BIOS/CMOS battery. Connect the AC adapter for just 3-5 seconds. Reconnect the BIOS/CMOS battery. Replace Base Cover and Main Battery. Connect the AC adapter. The system should try to reboot 3 times automatically. Best regards, U2
Help! I have this latitude e5440...this morning at 4am...i've been used my laptop for an hour then i turned it off....around 7am...i turned it on again but theres no screen, only black but my power led is on but the hdd led keeps blinking in a matter of minute then shutdown...what seems to be the problem? Ive already made all the minor sloutions like removing battery and hold power for 15 secs then turned it back on but no respond....please help i need this laptop for my work at home in thus pandemic times... 
e5440 power is on but no screen display and hdd led keeps blinking then shutdown