The heatsink on the evo is pretty big. I doubt that your cpu got fried in 20-30 seconds. The computer would have probably shut itself off if you did come close to overheating. I wouldn't worry too much about it. Just buy a new fan for your heatsink and start your computer up.
I would also like to add that the system might have shut down if the system detected 0 RPM on the CPU fan. My motherboard starts beeping after a few seconds when I try to turn it on if no fan is on the CPU fan plug or the fan isn't spinning.