went for a short blast and knocked out 25 miles at 20mph. Returned home pressed pause on the edge but for some reason instead of holding in the lap reset button I pressed the power button. Ride lost. They shouldn't allow that to happen I'm fuming
In general, powering down the Garmin (In my experience with a 200, 500 and 800) won't lose the ride data, it's ready to resume the ride when you power it up again, until you hold down the lap/reset button which ends that particular session and starts to record a new session.
It stores the data in whatever flash memory the unit has available (approximately 50Mb on a garmin edge 500), and the files are stored on the unit in the Activities folder, if you sort by date you may find your ride data is still there.
A more common problem is rider error, a rider will stop for a break and stop the timer, then fail to resume the timer when they continue their ride.