If your windshield wipers are stuck in the upright position, there are a few things you can try to fix the problem. First, check to see if the wiper blades are frozen to the windshield. If they are, thaw them out with a hair dryer or defroster. Once they're no longer frozen, try moving them back and forth to see if they'll budge. If they still won't move, try spraying WD-40 or another lubricant on the joints where the wipers connect to the arms. This may help loosen them up enough to get them moving again.
If your wipers are still stuck after trying these tips, it's likely that something is wrong with the wiper motor itself. This is a more serious issue that will require professional repair. In the meantime, you can try covering your windshield with a tarp or blanket when it rains or snows to keep it from getting too dirty.