Further to my previous answer, if you remove the front screen trim. Careful as it is very flimsy. Behind it is a very small button that is marked reset. You should be able to reset the device back to the factory settings with this button. You may have to use something like a biro to press it though. It will not clear the memory card but should take you back to original settings. I seem to remember that my problem was caused after i tried a language update from the Garmin site. Hope this helps.
DaveL
March 2007
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