Roy, Thanks for you help with the factory disk. Unfortunately it didn't work so today I tried another disk with older software (V 18.2). Someone had suggested to me that one it might be my best bet but it didn't work either. It was interesting though that the unit tried to read it for about five minutes before ejecting it. All the other software versions were ejected within a few seconds. I guess I have about run out of options unless someone thinks the unit needs some sort of coding or diagnostics prior to software installation. I did determine that it designed for a color screen so that's not an issue. The unit appears to be in good shape and the part number indicates a fairly late model MK III (Sept 2001) but maybe I just got a lemon. Any further thoughts would be appreciated as I think I am out of ideas. Thanks!

Yours is showing the exact same symptoms as my one did after I pulled the fuses to it, without letting it shut down properly.

It turned out to be an expensive mistake:dunno:

I finally gave up on it and went for A mk4.

so did you figure out if it was a coding ? os? or need a new navigation system?? i have the same issue need help

If you have a MKIII that lost power at the wrong time and is displaying this symptom, your nav computer is fried. You need to replace it.

I never got that MKIII to work. Once you get the "white screen of death" that's about it. I bought another MKIII locally that I was able to test in my car and it worked fine for about three months before it went dead with the same blank white screen. My alternator went out about a week later so perhaps there were some voltage fluctuations occurring that fried it. My recommendation would be to either move up to a MKIV or down to a MKII (plus the MKII Trimble unit) as the MKIII is just too temperamental.