My laptop cpu dead . What can I do?

I bought this laptop from a second-hand market for 330$. After 2 two months later I got received a message from my bios saying to “update your bios” but didn’t know what that meant. After 7/8 days my laptop wouldn't turn on. I took it to a repair shop and they told me I had a dead CPU. I attempted to search for one on the market but couldn't find one, Bcz it’s a market out in Bangladesh. After that, I decided I would change the whole motherboard. But sadly I couldn’t find a replacement anywhere. What can I do ?😭 please help me. I don’t have the availability to buy a new one.