What to do if the PC does not start?

Question

Computers

Good day, the story is this, I used a computer for 3 years, then in 2015, I took it to the country, closed it with a package and scored for 5 years. Not so long ago I needed a PC, I remembered about it. He took it, brought it, connected it, and after 3 seconds after starting it turned off. Took it apart, cleaned it, replaced the thermal paste. I connect it, and it no longer cuts out, but does not display an image, I tried two video cards, two different power supplies, nothing helps. I sin on the RAM, I can not put a replacement yet. Prompt, in what there can be a business.
Z.s. There are no video outputs on the motherboard. Also, apparently, there is no speaker on it

Answer 1

Is the cottage unheated? Then most likely trendets motherboard.
On good - to find and connect the speaker. (It costs a penny) then at least the squeaks will become clearer.
Check without cooling the processor - whether it heats up at all when turned on. Can't be afraid, keep your finger on it. If it gets warm - turn it off, we will think further.
It would also be good to check the RAM (by replacement or in another PC)