Monitors won't connect to PC?

Question

Iron

Good afternoon. Today, after the operation to replace the RAM, the computer refused to connect monitors. I complain either about my burned-out mother, or about the video card. The problem is, since my computer was left without monitors, I cannot see the connected devices. At the same time, purely visually, it seems to work. Coolers plow, he turns on, hards spin. Visually, the video card also works, the coolers spin, the light bulbs near the power supply glow. From the integrated vidyuhi there is no sense either, she also does not see the monitors, which may hint that the mother burned out. And here are a few questions:
1) If the mother burned out, the computer should not turn on at all? Or may certain components fail, but otherwise the mother will continue to function? Well, for example, if during the replacement I damaged the slots for RAM, will the mother work?
2) How can you still check what is out of order, the mother or the video card, if no visual information can be obtained? Neither look at the list of devices, nor connect remotely.
3) If the percentage suddenly burned out, what will happen to the computer? Does it not turn on at all? What in the computer itself can manage hard drives? Since they spin when turned on, they read something.

Answer 1

Thank you all, the issue was resolved by a simple reset of the BIOS, but for some reason one memory bar is now chopping off the computer, apparently the slot is still damaged.

Answer 2

If the percent burned out - the computer will not turn on. This, by the way, is the easiest to check - unfasten the cooler and turn on the computer for a couple of seconds - if the percentage warms up during this time (you can check with your finger) - everything is fine.
Hards are controlled by the I / O controller, which in the chipset on the mother Mother
is a technically rather complex device, so a lot of things can fail in it.
The chance that both the external vidyuha and the integracha died at the same time is small.
If the memory slots are damaged and her mother does not see, the computer makes a specific sound

Answer 3

Bring back the memory. And reset the BIOS.

Answer 4

We disconnect EVERYTHING from the motherboard (screws, memory, vidyahu, drives; we leave only the processor) We reset the
BIOS We
test by connecting one component at a time, starting with memory. On the Internet, you can search for a description of the number of beeps when something is wrong