Computer left in heat doesn't recognize monitors

Hello,
I left my computer in my car for a few days while moving. I live in South Carolina so it has been pretty hot the past few days. The power supply works because the computer turns on, but when my monitors are plugged in they say "no signal". I tried plugging them into my graphics card and into my mother board and nothing popped up on either try. My computer and mouse light up, so the motherboard is transferring power, but it doesn't seem like anything else is working. I've tried unplugging, holding power to drain any leftover energy, and replugging. The computer has had enough time to cool off and is now room temperature. Any advice would be appreciated.