Welcome, newcomer. There are two ways to determine if your mobo is "busted":
1. Damage: capacitors are leaking or bulging; scorch marks from spark/overheat
2. Part swap: using all of your parts (or at least the parts necessary to POST/boot) on a similar or identical mobo.
Unless there are physical signs of damage present, the only other way to distinguish between CPU and mobo would be to put the CPU in question on a different mobo (that supports the CPU) and also install a stick of RAM, the Power Supply Unit, the heatsink/fan, and GPU (video card). If you don't use a GPU, then simply connect the monitor to the mobo.
Just so you know, typically, the CPU is not the failing component in a "no boot" scenario. If you are experiencing a "no boot" or "no display" issue, click on the link in my signature.