Why does the computer beep when turning on?

Hi @kmbalad

A 5:2 error code indicates that the embedded controller cannot find valid firmware i.e. a possibly corrupted BIOS or a motherboard problem.

Try a full power refresh and check if that resolves the problem.

• Disconnect the power from the PC and then open the PC and remove the RTC coin cell battery from the motherboard.

You didn't specify what variant of a ProBook 400 G3 model you had e.g. small form factor, mini tower, so here's the maintenance and service guide for a Probook 400 G3 MT PC that may help.

Go to p.40 (49 of 139 pdf) to view the procedure to remove the RTC coin cell battery.

When the battery is out, measure its voltage. If it is <2.5V DC or if the battery is >4-5 years old, replace it. The battery model number is on the battery e.g. CR2032

• Press and hold the Power on button for a full 30 seconds and then release it.
• Reinsert the RTC coin cell battery (or its replacement) into the battery holder on the motherboard (+ve side up as marked on the battery).
• Reassemble the PC, connect the power to the PC and check if it turns on OK.

If it turns on OK there may be a message stating that the date and time are incorrect. This is normal as the BIOS has been reset back to its factory default condition by the above procedure. Once the date and time have been corrected, the message won't appear the next time that the PC is started. Also any user definable BIOS settings that were changed by you, to suit whatever system requirements you wanted, they will have to be changed back again as well.