Nope. Its just once. Not often. My psu is 500watt GOLD. And it should be more than enough for my system. But could you tell me what has happened?
MS Windows happened.
No but seriously, it's really hard to tell. Could be anything you see. Perhaps a failing storage drive, failing DIMM, possibly even a failing CPU...
For now I would advise you to just carry on normally since it only happened once. If it happens again, becomes more frequent, you'll know something's wrong.
I would run memtest just to make sure. As others said it just might be a glitch, often times if the PC hasn't been running for a good period of time. Is the PC new/used? Or have you used this PC for quite a while? Normally though any time you get a blue screen though it's a good idea to check out what stop error it produced. Checking with memtest (memory being your problem) won't hurt & you might even find out there was a problem. Also i'd make sure your PC is hooked up to a surge protector. It'll help keep your PSU from causing problems (not 100% protected tho, all PSU's fail at some point) & will help keep your system run smoothly.