Monitor keyboard and mouse wont work

Hello,
i have a problem when i boot up the computer itself seems to be fine it sounds a little loud and the fans never calm down (like they do when it finish booting windows) but the monitor and mouse dont work at all, absolutely nothing other than an orange power light from the monitor (its gets its power from the mains. i had just cleaned the fan of dust i think i may have knocked a wire but i cant see any loose ones i have made sure they are all plugged in correctly.

i think my CPU is a MS-7725 its a 77somethingsomething. i know that.