Question PC won’t boot, shuts off after 30 seconds?

Jan 28, 2020
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So i purchased an MSI B350 Tomahawk and an AMD Ryzen 7 2700x both used together for 5 months from someone else, but ended up not needing the parts so after never touching the parts i sold them yesterday. However, after putting these parts into their build, their PC won’t boot, the pc turns on, nothing is displayed on the monitor, fans spins and boot light comes on, but after 30 seconds the whole system powers off. Buyer thinks that this is a motherboard problem, any advice on what could be wrong?