CMOS checksum is invalid - CMOS reset (502) Error

[rabnl]

Own a HP24 All in One desktop PC. There are 2 issues to be addressed.

1. On bootup I observe a small window with error message "CMOS checksum is invalid. CMOS will reset to the default configuration & computer will restart. Afterwards please check the BIOS setup options to see if they change (Not checked). Then CMOS Reset (502), ENTER - Restart the computer".

What is the solution for the above problem. Can it be done by ourselves.

2. Small ants have entered in the PC. They are visible from outside when I see the screen but is within & in front of the LED screen. I find them moving around. Can create further problems in the long run.

Need a solution to this too.

Friends/community members, do put in your experiences & solutions for the above two issues. 

[VikramTheGreat · Accepted solution]

Hi @rabnl,

Welcome to the HP Support Community.
 

Thank you for posting your query. I will be glad to help you.

I understand how concerning it is to see both a CMOS checksum error on your HP 24 All-in-One desktop PC and to notice ants inside the screen. Let’s address both issues.

Issue 1: CMOS Checksum Error (502)

This error typically means the BIOS settings have been corrupted, or the CMOS battery is failing. You’ll see a message like: “CMOS checksum is invalid. CMOS will reset to the default configuration & computer will restart. Afterwards, please check the BIOS setup options…”

Recommended Steps to Fix CMOS Error

Step 1: Restore BIOS Defaults

1. Turn off your PC.
2. Turn it back on and immediately press Esc repeatedly until the Startup Menu appears.
3. Press F10 to enter BIOS Setup.
4. Go to the File tab and select Apply Defaults and Exit.
5. The system will restart.

If the error disappears, the issue is resolved. If it persists:

Step 2: Replace the CMOS Battery

• The CMOS battery is a small coin-cell battery on the motherboard.
• You can replace it yourself if you're comfortable opening the back panel.
• After replacing, restart the PC and re-enter BIOS to set the correct date and time.

🔗 HP Desktop PCs - Resolve BIOS ROM or CMOS checksum error | HP® Support

Issue 2: Ants Inside the Screen

Ants inside the display can be more than a nuisance; they can cause short circuits, screen damage, or even motherboard issues over time.

HP Recommended Actions

1. Power Down and Isolate

• Turn off the PC and unplug it.
• Move it away from food sources or warm areas that attract ants.

2. Do Not Spray Anything

• Never use insect spray or liquid cleaners inside or near the screen it can damage internal components.

3. Use Gentle Vibration or Light

• Place the PC in a well-lit area or gently tap the casing to encourage ants to move out.
• Some users have had success placing the PC near a low-heat lamp to draw ants out.

I hope this helps.

Take care and have an amazing day!
 

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Regards,

VikramTheGreat