My HP laptop often wont boot up

[Alain_Reve]

The laptop sometimes boots up nicely, but sometimes it doesn't boot up at all, and this is becoming more and more frequent. The white light blinking next to the caps lock key is also inconsistent. Sometimes I see 2 long blinks, sometimes 3 long blinks, sometimes 3 long and 1 short, sometimes no blink at all. Just nothing, the screen stays off.

I have a dual boot windows/ubuntu, when the laptop agrees to boot up, I sometimes see in the grub menu the message "error invalid environment block - press any key to continue".

I suspect a short somewhere, because another problem is that the laptop is uncommonly sensitive to movement. For example, if it is on the bed and I move a bit too much, it can abruptly power off, without any warning, as if I had suddenly pulled out the battery.

I hesitate to open the laptop, because last time I opened one up the keyboard ribbon moved and the keyboard became unusable. This is the laptop I'm using to write this, with an external usb keyboard. The HP didn't boot up this morning. Additionally, I can't remove the battery before opening it up, which is worrying. I'll check this up before buying the next laptop.

If I open it up, how can I find the cause of the problem? Buying replacement parts is OK, but which ones? It's like when my car stopped. I called a friend. He asked me whether I had opened the engine compartment, I said yes. He asked "And?", I replied "Well, there's an engine inside". He said he was coming right away.

I'm wondering about the UEFI usb boot key, used to diagnose hardware problems, exe file available for free download here:

https://support.hp.com/us-en/help/hp-pc-hardware-diagnostics

Luckily the laptop is set up to boot from usb before hard disk, but I'm not sure at all it would boot from that key... Or, if it's in one of its good days, maybe it will and then tell me everything is OK. Because, when it does boot up, everything functions fine.

All suggestions welcome