Is there a way to determine if my PC is killing my monitors that doesn't involve killing another monitor?

"This is probably just random bad luck. This is more likely if both monitors are about the same age, and made by the same manufacturer. Also, the monitors failed in different ways.

If you suspect your AC power, your outlet tester will only show you whether or not your wall outlet is wired correctly. A multimeter will show you whether or not the AC line voltage is OK. To look for anything more advanced, such as surges, spikes, and dips, you will need a -very- expensive power line tester.

If you suspect the graphics card, you will want to look at the graphics card video output. To do this, you will need an oscilloscope instead of a multimeter."

It's unlikely to be the computer that's causing the dead monitors. The highest output from a vga port is 5 volts on pin 9. The pins for the red, blue and green data should be around 0.7 volts. If the computer was pushing more power through the port than this it probably would have instantly fried the monitor instead of working for another day/week/month.

"Given your back story I think you need to run a full battery of tests on your wife, culminating in a human centrifuge set to 4Gs.

In all seriousness, while this is likely a coincidence based on two older monitors dying, you should suspect the power supply and shared components rather than the PC. A power conditioner could help. If during your tests you spot your wife turning on the whole mess of PC, Monitor, Speakers, Printer, and Scanner on one power-strip with one flip of a switch, then that's your problem there. Other problems are being hooked into the same power that an office-copier uses (damn those toner warm-ups), an air conditioner, or a refrigerator (compressor starts and stops). If your wife is like mine, and thinks a space heater or humidifier near the PC is toasty fun or soothing respectively, you need to calmly explain electronic environmental limits.

If you must break out the toys, get a multi-meter, an AC grounding tester, a trip monitor (it lights up once the voltage drops below 100v, and again if it peaks 125v), and an amperage gauge. These are fun because you can loop it around the power cable, and see what happens when you turn stuff on. An oscilloscope is an indulgence you probably can't use to accurately gauge anything unless you've already used one for a while."