If there is no pc speaker, hook one up. (not the sound card speaker, but the one using the headers on the motherboard.) If it is hooked up and doesn't beep, it's more then likely the processor or motherboard. Check to see if any capacitors are blown on the motherboard as that is the likely thing to break on one.
If it does beep, then it means that the motherboard is more then likely not dead. 3 beeps is normally ram. If you have two sticks, take one out and try again, if it doesn't work, swap sticks of ram and try again. If it still doesn't turn on and beeps, you'd have to find who made the bios and get the beep codes for that company. More then likely if it beeps, it can be fixed, but you HAVE to have the case speaker hooked up in order to know if it's beeping. It won't turn fans on or anything if it's throwing a beep code in 99% of motherboards.