kittymer -- I have the same problem on my 2006 Limited, 85000 miles. When I turn the car on, a message pops up on the screen that says "system loading. Do not turn of the power". Sometimes it comes up, sometimes it doesn't. When it does come up, the radio comes on, but won't stay on consistently -- goes in and out. And the navigation is all messed up (in the few instances where it does come on -- it doesn't stay on long). I'm not an electronics expert, but I'm convninced this isn't a "need a new MAP DVD" issue. There's something failing electronically. I'm fearful that it could be something like others mentioned earlier, like the power supply or something on the motherboard. I'm taking it to the dealer tomorrow to see what they say, but I went to a "Car Toys" store here in the Denver area and tried to describe the problem to them. They don't do repairs, a new in dash Radio / Nav / CD with the rear flip down DVD would cost me around $1700 - $1900 installed, depending on what features I get. Hopefully, the dealer will come up with another alternative (like the refurb option mentioned in one of the earlier posts)
*** Quick update: System has now completely failed, but I was fortunate enough to at least get my Map DVD ejected before it failed. Found a guy in Michigan that does refurbs of these units with a 90 day warranty and a $300 Core Charge (refunded when I send my defective one back). Found him on Ebay under the name toyolexnavspec. Unit should be here soon. Installation should be pretty easy -- youtube videos out there showing how to remove it. It's plug and play, so hopefully I'll be back up and running by Tuesday night... Will update once I get it installed.
*** Quick update: System has now completely failed, but I was fortunate enough to at least get my Map DVD ejected before it failed. Found a guy in Michigan that does refurbs of these units with a 90 day warranty and a $300 Core Charge (refunded when I send my defective one back). Found him on Ebay under the name toyolexnavspec. Unit should be here soon. Installation should be pretty easy -- youtube videos out there showing how to remove it. It's plug and play, so hopefully I'll be back up and running by Tuesday night... Will update once I get it installed.