If both stopped at once, it's probably NOT the switches. Probably a fuse. Replace the fuse for the power windows, whether it looks OK or not. Sometimes fuses look OK, but the contacts are corroded/dirty, and it stops making contact...That's probably the culprit.
If not, you may have a shorted wire somewhere BEFORE the switches. If the fuse IS actually burned out, and you replace the fuse, and it happens again, DON'T use a larger-amp fuse. Find the short!
Regardless...the odds of both switches going bad at exactly the same time are VERY slim.