HP Omen 15 will not boot after replacing fans

[save_our_reef]

Hello! I did a stupid thing and unplugged but forgot to remove the battery before replacing the right fan which had been noisy and basically not working. Everything was great! So I thought it would be wise to replace the left fan, also before problems developed. But then the laptop was totally dead.  (The new fans were sold as a pair so no compatibility problems).  Note: the battery remained installed through both fan replacements. 

--- I have followed several videos, removing all power sources, and disassembled / reassembled almost the entire laptop several times.  Checked connections, ribbons, etc. Is there anything else I could have missed that is more obscure? There is a white light next to the power cord when plugged in. But no other response. Could I have fried something by leaving the battery in during the initial fan replacements? How do I diagnose an unresponsive laptop? Or is it time to find a pro? 

---Thanks

[VikramTheGreat]

Hi @save_our_reef,

Welcome to the HP Support Community.
 

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

I can feel how stressful this situation is, especially after putting in the effort to replace the fan,s and now the HP Omen 15 won’t power on. Based on what you described, here’s what likely happened and what you can do:

What Might Have Happened

Leaving the battery connected while replacing internal components can cause:

• Short circuits if metal tools touch live contacts.
• EC (Embedded Controller) or motherboard damage due to static discharge or accidental bridging.
• Corrupted power state (laptop stuck in deep protection mode).

The white light near the power cord means the charger is detected, but the system isn’t completing POST (Power-On Self-Test).

Step-by-Step Diagnosis

1. Perform a Hard Reset
   • Disconnect the AC adapter.
   • Remove the battery (internal).
   • Press and hold the Power button for 30–60 seconds.
   • Reconnect AC adapter only (leave battery out) → Try powering on.
      
2. Check for Life Signs
   • Any fan spin, keyboard backlight, or Caps Lock blinking?
   • If no lights except the charging LED, the motherboard may be in protection mode or damaged.
      
3. Inspect Ribbon Cables
   • Double-check the power button ribbon cable and keyboard connector.
   • If the power button cable is loose, the laptop won’t start.
      
4. Remove CMOS Battery
   • If accessible, disconnect the CMOS battery for 10 minutes to clear any corrupted state.

• Reconnect and try again.

I hope this helps.

Take care and have an amazing day!
 

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Regards,

VikramTheGreat