I had same problem on 3/28/09.
According to Magellan and other people who have experienced the same problem, this is terminal to the unit. It can be caused by downloading the 08/09 Magellan map upgrade
, which can cause the unit to permanently lock up. Magellan is well aware of the problem, and should offer to replace your unit if you have the problem. If you elect to have it repaired, Magellan can download the map upgrade for you in the repair process. Here is a site noting the same problem: http://18.104.22.168/search?q=cache:pNLjGT-i4-sJ:forums.gpsreview.net/viewtopic.php%3Ft%3D8958+magellan+4250+gps+stays+on+blue+screen&cd=8&hl=en&ct=clnk&gl=us
Questions for Magellan: 1) why would they sell, in 2009, gps units with old 2007 maps loaded in them, requiring the purchaser to buy a current map, and 2) if there is a problem with downloading the current maps, why is there not an advisement or warning to the installer.
Other than replacing the unit, there appears to be no "fix".