I second Rounik's diagnosis... your preference file got corrupted as a result of the power outage.
Please, please, do yourself a huge favor and buy a UPS -- an uninterruptible power supply. It's the best gift a digital musician can give theirselves! Even if you think that that outage was a fluke, things like this can happen more than you might like to think, especially when you're living off of batteries. (And congrats on that, btw. I'm now officially jealous! Me and my wife have talked about converting to solar and, cash willing, one day we'll do it).
I've attached a link below to a place where I've purchased my UPS's from which has great deals and great technical support too. I used to live in an area with frequent power outages, and these became indispensable. But now that I live in earthquake country, they're running my system full time. In case of an outage, I can run my entire studio off of my UPS's for 1/2 hour (and stay on the internet too!!)
Go for one of the "Smart UPS" models. Actually, let me stress, "only buy one of the Smart UPS models". One of the tower models should be just fine (I have two). Avoid the rackmount models, though, as they're very very noisy.