Although it's not impossible for two PSU's to fail in the same computer it is a little suspicious. My immediate thought is that maybe it's possible your either encountering surges and/or other power brown outs that are causing it to fail prematurely.
I'd suggest getting a different surge protector (preferably a higher quality one), not a cheap one that you find on the shelf at a grocery store and/or if it's in the budget maybe a UPS with a surge protection.