» Fri Jan 04, 2013 12:04 pm
Was this a horse that you purchased from a stable, or one that you just found somewhere and were able to ride?
If it was the former, then it should stay wherever it was when you dismounted, unless it ran a little ways away to get away from the fight, and then it should stay there until you go get it. I suppose if you left it waiting long enough it might head for home on its own, and that should be the stable where you bought it. If it's still alive it should either be there or on its way there or still standing somewhere around the spot where you last rode it.
If it was just a random horse you found somewhere, as soon as you dismounted it would have started walking back to the spot where you found it. If it's still alive it should either be there or on its way there.
If you leave your followers for too long and they don't die, they will also head back home on their own. Return to your follower's home and see if he/she is there. If the game is telling you that you still have a follower, then unless something got bugged he/she should still be alive.
Keep in mind though that both horses and followers will walk all the way when returning to their homes so depending on where you left them and where "home" is, it can take a while.
If they are alive, though, they should both turn up at your location if you fast travel. If you fast travel somewhere and neither your follower nor the last horse you rode turn up in the same location with you, then the horse is dead and your follower is either dead or has left your service (in which case the game is glitching out by not recognizing that). Who was the follower? A housecarl? A hireling?