hopefully you have not given up yet....
When you turned the unit off after inserting the SD card with the original extracted AutoUpdate_Eng_Untouched.rar, did you remove ALL power to the unit? For example, did you disconnect it from all the power sources in the car, and let it sit for a day or so like the instructions say?
1. download the AutoUpdate_Eng_Untouched.rar file below and extract it to a clean fat formated sdcard keeping the folder structure (eg. nwdtcali.exe nwdsoftware.exe in the root & .msk, .bin, .nb0 in the autoupdate directory)
2. turn on the unit and put it in the "gps" sd card slot.
3. turn off the unit
4. remove the unit from all sources of power (it has a couple of power sources so you need to get both disconnected completely) and leave it disconected for at least a day. this may not be nessecary but i had removed my unit from the car and had it sitting with the sdcard in for a day... then when i powered up the unit, the update began automatically (i had tried this many times with the unit in the car connected and it never worked) i have also read many people saying they have removed internal batteries to get there handhelds to fire up.
5. after a day, reconnect power, turn on unit & select gps area
6. after a few seconds a systemupdater screen will appear and the process will proceed for about a minute then finish
7. when the updater is finished/succeeded and the exit button is visible, press it.
8. REMOVE THE SDCARD NOW... if you dont, it will do it all again
9. turn off unit at front button
10. turn unit back on
11. recalibrate screen
12. your working again