I need to know the cause of the problem, and I hope the man

@nadyghatta21480 to set the time you need to access your system setup:

1. Turn on (or restart) your computer.

2. After the white Dell logo appears, press F2 immediately. The System Setup page is displayed.

NOTE: If you wait too long and the operating system logo appears, wait until you see the desktop. Then, shut down or restart your computer and try again. NOTE: After the Dell logo appears, you can also press F12 and then select BIOS setup.

On the General screen that no shows you will see the Date/Time option. Use that to change the date/Time to the correct one.

If the time does not stay adjusted it is entirely possible that your RTC (Real Time clock) battery needs to be replaced. Use the Dell Latitude 15 5580 Manual and check page 18 for the instruction on how to change the coin cell battery.