BIOS error(out of date) frequent message

Hi TARMOH,

Are you using an original Dell OEM Adapter? Is the adapter frayed? Could you test with another power adapter if possible? 

Restart the system and press f2 key to enter BIOS - check the adapter status in BIOS with and without the adapter plugged in. Also, wiggle the adapter cable at the end and see if the status changes in BIOS at any point. Check the battery health in BIOS (if applicable).

If possible, update / flash the BIOS - http://dell.to/2dcAKFq

Restart and enter BIOS and reset defaults - save and exit and check again. Also, ensure the time in Windows is set to current local time and date.

If the issue is still unresolved, then download the service manual here - http://dell.to/2cEg4VT - and reseat the cmos battery and check.

If it still does not work, then replace the CMOS battery, you would need this part - http://bit.ly/2cOxWuM

If the issue stands unresolved, then you would need to replace the motherboard. 

Personally, I would suggest you to invest your money on a new machine than to repair this old system.

Also, please click my DELL-username and write me a private conversation with the service tag and your contact details(Name and Email) for case records.

Let us know if you have any other queries.

Its a fairly old model likely the CR2032 coin cell battery on the motherboard is flat and due for replacement. Its relatively easy to replace however requires a disassembly. See the service manual for details:

http://ftp.dell.com/Manuals/all-products/esuprt_laptop/esuprt_inspiron_laptop/inspiron-1525_service%20manual_en-us.pdf