Why does the PC only boot after a BIOS reset?

Question

BIOS

Conducted maintenance of the system unit, cleaned it. Installed a new cooler as the old one broke.
I put everything back together and there was a problem: now the PC turns on only after a complete reset of the bios.
After downloading it works perfectly fine, tested with WOT.
If you restart the PC or turn it on, nothing happens after turning it off. Fans turn on, but even bios messages are not displayed on the screen. The motherboard has a screen showing bios error numbers. It shows how the numbers begin to change, but everything ends with two dashes.
As soon as I take out the battery and reset the bios, the PC boots normally.
Motherboard: Foxconn cs1xem2aa. In the instructions for it in the error table, there is no description of the situation when there is no error number, that is, when there are two dashes.
Tried disabling various components. CD-ROM, sound card, etc. It doesn't change anything at all.
I tried the following: if you turn it off in a regular way, remove the video card and try to turn it on, then bios does not report the absence of a video card, and also stops with an error with two dashes. However, if you reset the BIOS, then it conducts a self-diagnosis procedure and reports an error number about problems with the video card.

Answer 1

Firstly, the mentioned jumper is not intended to be turned on (off). Switching it for a few seconds from the NORMAL position to the CLEAR CMOS position is similar to removing the battery (it's just more correct than "pulling" the battery). Before turning on the system block it must be returned to the NORMAL position. Manipulations with both the jumper and the battery must be performed with the power supply of the system unit disconnected from the 220V network.
And secondly, at 2.09V, it's time to replace the battery.

Answer 2

Collected at the stand. On the motherboard, I left only one memory bar, a video card and a processor with a cooler. Problem still exists.
The problem was solved by replacing the mat. fees.