I have found that damaged or faulty power supplies can often cause problems that seem like other things as well. You should check that as jaydeejohn said while you troubleshoot other items. I recommend checking it first though and checking it off your list. You just need to go down your list of hardware eliminating each as the source of your problem. Process of elimination works for lotta other things too.
Each PSU has a 3.3 volt, a 5 volt and a 12 volt
Obviously, you dont want it too high or too low from those given values.
Testing it, or testing the output should be done under varying loads, such as a stressful game, where alot of your hardware is being used close to capacity, as well as at idle, and maybe a midpoint as well, maybe a less stressful game for instance.
If your voltage levels remain mostly stable, and dont dip or even possible peak high, then most likely your PSU is OK.
Then go from there, checking your cpus heat, see whats normal for it, as well as your gpus, as each component has its own operating temp/power draw
As you stated above, you don't have any problems that you know of, if you go searching may not find anything and if you do, you don't know if it was a problem from before the power surge. All I can say is, fix any you find and get a surge protector.
An outage can't damage a video card, a surge that accompanies and outage could but it's pretty unlikely, and everything wouldn't "seem to be working fine" if it had. Why are you worried about it if everything is working fine?