Hi,
1. Power Off notebook, disconnect AC adapter and all other device connected.
2. Press power button and hold it for 15-20 seconds.
3. Connect AC adapter
4. Press and hold Win+B key, keep holding it and press power button
5. Release Win+B key after 5 seconds approx
If it's same,
Check if caps lock is turning on / off
If yes, Check with external monitor or TV.
If display comes in external monitor/TV, then notebook display may required to replace.
If caps lock / external monitor/TV also does not display, suggest to call and contact with HP Support as it could be hardware issue.
Thanks & Regards
VG
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Thanks & Regards
VG