[x86-64] Can't Boot After Completing Installation

Hi. I decided to transfer my Lenovo H505s desktop PC to HTPC. So I've created LibreELEC bootable USB and booted to loader. In the menu (where boot options can be chosen) I pressed 1 and Enter. "No such file or directory" (What? Why?) Anyway few seconds later installer started. After Installation was complete I removed USB and rebooted. But it`s not possible to boot because of Error 1962: No operating system found. Press any key to repeat boot sequence."

I can`t find any solution for this problem. I googled that, but all I could find is that some Lenovo PC not support Linux installation (my Lenovo had preinstalled Windows 8 by the way). I tried to install Ubuntu 20 - it can be loaded after install, but I don`t need Ubuntu. Also tried LibreELEC 9.0.2 and OpenELEC - same result (can`t load after install complete)

Found this: UEFI Mode installation of Linux distributions on Thinkstation S30-English Community - but I don`t know how to apply this solution to my issue.

Sorry for my English, learned it in school loooong ago!

Thanx for reply. I must add more info:

I can't boot Ubuntu Live CD in UEFI mode - after Lenovo logo appears PC just freeze and I can only switch it off with Power Key long pressed.

So, I can only boot in Legacy mode. But when I booted Ubuntu Live Installation Media in legacy mode I'm not allowed to change EFI variables!

I asked Lenovo support, and they answered that my PC motherboard (Lenovo h505s desktop) supports only windows 7 and 8.1!

I guess that solution of my problem exists... Maybe I just need to attach my HDD to another PC and install LibreELEC, then I connect it back to my Lenovo PC? Will it work? )))

Unfortunately I can only boot (Live CD or Installation) in Legacy mode. Only Legacy Mode works for my Lenovo. In EFI mode I can boot only until Live CD menu appears, but when I choose Ubuntu (or Ubuntu in Safe mode) it shows me LENOVO logo and freeze, like I wrote before. So I can't see the way to somehow load it in EFI.

BUT, I made my experiment )) And it worked fine... Everything seems work well. I'm now writing it from Chrome Addon from LibreELEC repo!

What I've done:

1. Removed HDD from Lenovo and connected it to another PC (by the way, my Lenovo has AMD CPU, and another PC has Intel)

2. Installed LibreELEC from USB in Legacy mode to HDD from Lenovo PC.

3. Reconnected HDD back from another PC to Lenovo.

4. Profit! (Yes, it still runs in Legacy mode only, but it finally works!)

Well. I guess, you meant this link http://ix.io/2sWg