Thanks again for all of your comments on this thread. Sorry I haven't posted this sooner, but I've been busy with work and all of that. I was able to discover and subsequently fix what was causing this computer freeze/no boot issue. It turns out there were three bad capacitors on the motherboard, one of which was bulging out on the bottom; was able to remove the old caps and solder on three new ones. Computer is back in business.
Not really permanently resolved. If you have three now, you will have more later. What you did is only a temporary fix.