Unplug it and plug it back in if it still doesn't start working make sure you have power to that socket by plugging something else into it. Check for impediements...bushes, branches, snow, etc. Clear anything you can off the wires. Did you have an electrical storm or anything? Lightning can kill a fence charger faster than anything especially if the fence isn't properly grounded. If the fence charger doesn't work when plugged into a different outlet then time to take it to see if it can be repaired. Sometimes your local farm supply store will know someone who you can send it to. We've had the same charger for 18 years but it is well grounded and my husband checks the fence with the fence tester very often. I look at the charger every day to make sure it is on/plugged in.
"My biggest fear is that when I die my husband is going to try to sell all my horses and tack for what I told him they cost."
My fencer has fuses in the plug. On rare occasion, they blow from a lightning strike. But I recall at least once, they just wore out. (The fencer itself is over thirty years old.)
I can tell from the "click" (light indicator faded out years ago) if it's shocking good, or if there's "stuff" on the fence (weeds, etc), or if there's a total short (fence on the ground or touching steel post), or if there is nothing at all (unplugged, thingie on outlet tripped, or fuses shot).