Bios issue error502

[misternaad]

Hello, i have this error when i'm starting my computer :
The CMOS checksum is invalid.
The CMOS will be reset to the default configuration and will be rebooted.
Please check your BIOS Setup options to see if they change.
CMOS Reset (502)
ENTER - Reboot the system
For more information, please visit www.hp.com/go/techcenter/startup

how can i solve this problem please ?

[misternaad]

i forget to tell you that i remove the battery from the computer (i almost never use it and and i want to keep it safe from age and be able to use it when i will travel one day).

i also add an HD 1To SATA 

but i don't understand why i have this problem ??

[Riddle_Decipher]

@misternaad To resolve a BIOS issue, install the latest BIOS for your computer. See Downloading or Updating Software and Drivers for HP Computers for more information.

Refer to one of the following links for information about restoring the BIOS on your computer:

• HP Notebook PCs - Restoring the BIOS

If that doesn't work, I'm afraid this is a hardware malfunction and I suggest you talk to HP support and discuss your options, follow the below steps to get started:

1) Click on this link - http://www.hp.com/contacthp/

2) Click on Sign-in or select the product using the below step:

3) Enter the serial of your device.

4) Select the country from the drop-down.

5) Click on "Show Options".

Fill the web-form, to populate a case number and phone number for yourself!

Also, if you are having trouble navigating through the above options, it's most likely because the device is out of warranty, if yes? please send me a private message with the region you are contacting us from, 

here's how private messages work: Click here for details.

P.S: Welcome to HP Community 😉

If you wish to thank me for my efforts, you could click on "Accept as solution" on my post as the solution should help others too.

[misternaad]

i already upgraded the bios, i wanted to know, do this machine has a button cell ? (because i removed the battery) so maybe the bios can't keep informations because there is no button cell...

[Riddle_Decipher]

@misternaad If by button cell you mean the CMOS battery, then yes, and here's all you need to know about it: click here, Although I must let you know that HP does not support or recommend replacing it on your own, if you feel there's an issue with the same, please contact the support team as requested earlier and they'll help you out.

P.S: my last post recommended a BIOS recovery, if you have tried that and it didn't work either, please contact the support for assistance.

Good luck!