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- HP Community
- Desktops
- Desktop Boot and Lockup
- Desk Top won't start easily

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07-30-2025 10:50 PM
My desktop won't start easily, after couple of times restarting my system and pressing some key it shows up and say CMOS reset (502). All this easily consume 15 to 25 minutes.
Kindly advise. I am not a technical guy.
Thank you
Solved! Go to Solution.
Accepted Solutions
08-01-2025 12:03 PM
Hi @RajeshKA,
Welcome to the HP Support Community.
Thank you for posting your query. I will be glad to help you.
Thanks for reaching out, and I understand how frustrating this must be, especially when it takes 15–25 minutes just to get your desktop started.
The CMOS Reset (502) error typically means your computer's BIOS/UEFI settings were reset, often due to a failing CMOS battery or a hardware issue. Here's what you can do, even if you're not very technical:
Simple Steps You Can Try
1. Power Cycle the PC
- Shut down the computer completely.
- Unplug the power cable.
- Press and hold the power button for 15 seconds.
- Plug it back in and try turning it on.
2. Check the Date and Time in BIOS
- When the PC starts, press F10 (or Esc, then F10) to enter BIOS.
- If the date and time are wrong, it’s a strong sign that the CMOS battery is weak.
3. Replace the CMOS Battery
- The CMOS battery is a small coin-cell battery (usually CR2032) on the motherboard.
- You can ask a local technician to replace it; it’s inexpensive and takes just a few minutes.
4. Update BIOS (Optional)
- If you're comfortable or have help, updating the BIOS from HP’s Official HP® Support might help.
- Let the site detect the desktop model number and update the BIOS.
I hope this helps.
Take care, and have an amazing day!
Did we resolve the issue? If yes, please consider marking this post as "Accepted Solution" and click "Yes" to give us a helpful vote - your feedback keeps us going!
Regards,
VikramTheGreat
08-01-2025 12:03 PM
Hi @RajeshKA,
Welcome to the HP Support Community.
Thank you for posting your query. I will be glad to help you.
Thanks for reaching out, and I understand how frustrating this must be, especially when it takes 15–25 minutes just to get your desktop started.
The CMOS Reset (502) error typically means your computer's BIOS/UEFI settings were reset, often due to a failing CMOS battery or a hardware issue. Here's what you can do, even if you're not very technical:
Simple Steps You Can Try
1. Power Cycle the PC
- Shut down the computer completely.
- Unplug the power cable.
- Press and hold the power button for 15 seconds.
- Plug it back in and try turning it on.
2. Check the Date and Time in BIOS
- When the PC starts, press F10 (or Esc, then F10) to enter BIOS.
- If the date and time are wrong, it’s a strong sign that the CMOS battery is weak.
3. Replace the CMOS Battery
- The CMOS battery is a small coin-cell battery (usually CR2032) on the motherboard.
- You can ask a local technician to replace it; it’s inexpensive and takes just a few minutes.
4. Update BIOS (Optional)
- If you're comfortable or have help, updating the BIOS from HP’s Official HP® Support might help.
- Let the site detect the desktop model number and update the BIOS.
I hope this helps.
Take care, and have an amazing day!
Did we resolve the issue? If yes, please consider marking this post as "Accepted Solution" and click "Yes" to give us a helpful vote - your feedback keeps us going!
Regards,
VikramTheGreat