fagetti :
Are you sure your pressing the right key to get to bios? You said that pressing ctrl alt del when you see message restarts the laptop? This means your usb keyboard is working
Hello i'm back
I took out the digitizer and the keyboard connector was clean. The board had tiny bits of grains of cookies or dirt very micronized, almost nothing, I cleaned them with a board brush anti-static and placed back and installed the oem keyboard with the same old results:
1. caps lock flashes 2 times then pauses.
2. bios seems to pickup and press esc message runs.
3. oem keyboard is dead, cant access boot , startup or bios options.
4. I am unable to boot the machine with the usb keyboard, BlackSOD and usb keyboard lits but it seems unresponsive to esc key, f9,f10 or f11 ( the hp bios keys) . Is just that its BlackSOD.
5. If I boot it without the usb keyboard, it displays press esc and then the drive error, boot mgr is missing press ctrl alt esc to restart then, I plug the usb keyboard and it responds to ctrl alt del and the machine restarts to a BlkSOD again.
6. I have tried to boot it from an external usb flash drive and usb dvd drive, can't get them to boot from there with usb keyboard or with oem keyboard.
7. took out the hdd and place it on a sata to usb caddy adpter and tried to fix the mbr, I can't access the bootrec/fix mbr in my win 8.1 laptop, maybe with software but I'm able to see the partitions of the dv4 hdd.
To fix this I have to change the boot order or fix the mbr and I can't do it in the DV4. I think the only way is to fix the hdd OS or the mbr or an Ubuntu install in my laptop with the HDD drive caddy connected . The other way is to order a replacement oem keyboard and try to access the boot order in the dv4.
My conclusion is that the oem keyboard is shorted and outputs false and misleading caps lock error flashes.
The computer booted to Win 10 after the eeprom bios programming but some functions where odd and some errors of the win 10 recovery partition (out of space, or full) . I proceeded to reset the machine because I wanted Win 7 back and the reset was not completed or interrupted for some reason.
here are fresh pics of the board and keyboard connector.
well, thanx and sorry for my late reply's but Ill keep troubleshooting from time to time.