Question PC turns on but no signal on monitor and keyboard and mouse

[nigox]

so i have a quite old lenovo pc and one day after i boot up there is so signal on my monitor and no power on keyboard and mouse, i tried to put my vga cable into the mother board and it worked, i waited like 2 hour and then i put my pc back where it was and didn't work anymore. i tried every solution possibile, like changing cables, reset bios, changing monitor, someone can please help me out

 

[Colif]

One possible cause is the power supply. Often if it lacks power, it only supplies power to the necessary parts of the pc, those being CPU & RAM. Its common for all USB & the monitor to not work.

As its an old PC, its possible.

 

[DaleH]

so i have a quite old lenovo pc and one day after i boot up there is so signal on my monitor and no power on keyboard and mouse, i tried to put my vga cable into the mother board and it worked, i waited like 2 hour and then i put my pc back where it was and didn't work anymore. i tried every solution possibile, like changing cables, reset bios, changing monitor, someone can please help me out

Not clear what you have done. You said you put your VGA cable into the mother board and it worked. Where was it before this? The output connector on a graphics board? If so, then that tells you what's wrong.