I've got exactly the same problem, except the worst thing is that it is my friend's mk3!
So it's bad! I've taken the mk4 out of my car and put it into his while I try and revive his mk3. I had same symtoms, started upgrade (v26) and then the screen just went black. Stayed like that for ages. Then the disk wouldn't come out. Eventually figured out how to get the disk out, held the eject button for about 3mins, the light went out, then press eject and the disk *should* pop out. See here
http://www.xoutpost.com/articles/all-...ion-drive.html
Anyway, put in another copy (v22.1), and it still didn't like it. Except this time it didn't even say "Updating software...", just nothing. I've had this problem in mk4 but as soon as I burnt a new copy it was fine. And then the cd wouldn't eject at all, no matter what. So I took the top off and wound the cog round. Ejected very easily (and took less than 3 mins!). I wound it with my finger and used a small screwdriver to stop the cog from spinning back while i repositioned my finger. I didn't want to damage the cog.
My next try is burn another copy of the cd using Jochen's instructions
http://www.xoutpost.com/navigation-sy...heres-how.html. My cd's aren't called nav_sw and not done in mode2 burn.
Incidently, all my cd's so have have had a new splash screen added, I wasn't sure which one my system would use so I edited all of them, including the mk4 nav_boot file. I hadn't read this article and saw the splash screen in the usw_load file in NavTweak so thought I would give it a go. I thought that was possibly why the update failed, but obviously not!
Good luck and let me know how you get on. I hope I can fix this otherwise I'm gonna have to get him a new one!
On a side note, I read the thread about changing the VIN and vehicle type using NavCoder and IBus interface. It also mentions loading language fiules from disk. Anyone know if can you reflash the whole eeprom using this method? An alternative maybe if I can't get this working using the disk update method maybe.
thanks
Kam