This would be the time I'd start accusing poltergeists. I know they live in my home office and do all kinds of mischief at night while I'm asleep. They've only killed one Samsung LCD monitor here.
In the real world, it's likely a terrible coincidence. It's slightly possible that your APC unit allowed a nasty power glitch to pass in to these guys and kill them. That would be harder than winning the lottery. It's most likely you ended up with the statistical anomaly of two bad LCD monitors, along with that video card and motherboard.
Do you have a lot of power outages and glitches? Do you live in lightning alley or some area with lots of thunderstorms? I still remember the night when there was a thunderstorm here and I saw bolts of electricity flashing along the chain holding the ceiling fan in our bedroom. I fully expected to go downstairs and find our computers in a smoldering pile on the floor. Nothing - fully protected by APC UPS units! Then there was the time at work when a guy hit a power pole with his car down the street and caused a 27,000 volt line to fall on the 600 volt line feeding the building where I work. There were two washing machine sized APC UPS units in the lab - they both were fried and took some PCs with them.
I know this may not help much, but you may have enjoyed reading it.
Bye.