Computer Savvy people please respond, Would only like actual Computer-Smart people to answer.?

Had a computer that was working fine until one morning where it would whirr for 2seconds that turn off. Eventually i found that If I took out the CPU I could hear fans and boot up sounds but no monitor response. Tried on several monitors. After a few days, same responses with CPU in. I then found the CPU was blackened on the backside-But computer had same response with new Processors, I ume it's Motherboard but would like a definete yes from a Computer Technician.