The computer does not turn on, what should I do?

Question

Iron

Basically turn on the computer. All systems work except: Mouse, keyboard and monitor.
I tried to change the video card, wiped the contacts on the RAM, even changed the railway. Nothing helped, what should I do?

Answer 1

More information is needed, in particular:
What it looks like
1. If there are bios screens, it looks like broken drivers, it is checked by booting from a live cd
2. Problems with the mother, check by resetting the bios and replacing the battery, if it does not help, replacing the motherboard

Answer 2

Check if the speaker (speaker) is connected to the motherboard. Take out the RAM, turn it on, any signals? If not, then something with the power of the processor, or with the processor itself (unlikely). If there is, insert a RAM and try to turn it on with a different video card.

Answer 3

Try to remove the RAM and turn it on. If it's the same, then it's most likely the problem.