Thanks for the update. Since the CMOS reset didn't fix the 'HECI disabled' error, the issue might be with the Intel ME firmware region in your BIOS.
To ensure a full CMOS reset: with all power disconnected (AC, main battery, CMOS battery), did you press and hold the power button for ~30-60 seconds before reconnecting?
Do you have an external SPI programmer (like CH341A)?
Do you have an original, unmodified backup of your BIOS from before this problem started?
If you have a programmer, the absolute most important first step is to make a verified backup of your current BIOS chip, even with the error. Save this backup securely.
Once you have a reliable backup of your current BIOS, you could then consider trying to flash a BIOS dump. The link i`m found on badcaps.net (
https://www.badcaps.net/forum/troublesho...e7270-bios) might contain a working dump for your Service Tag (5DXYQC2). However, proceed with caution and only after securing your backup.
Let us know if you have a programmer and if the detailed CMOS reset changes anything.