I have no direct experience with the 410 but generally the first time a unit is turned on after a long period it needs to receive fair bit of information from the GPS satellites before it can determine it's position. To do this leave it somewhere with a clear view of the sky for a half hour or more.
I've moved your post to the Magellan section of the forums where hopefully someone familiar with this exact model will help.
Edit to add: See http://gpsinformation.net/main/slowlock.htm
for information on the two types of data, Almanac and Ephemeris.