thank's a lot everyone! and especially you ldotsfan who showed me to a package not yet tried but that actually worked!
or at least the box booted.

i couldn't format my new drive with the disc, it refused to open the xbpartitioner and a change in evox.ini made the disc useless.
but, however, it is not that hard to format the harddrive via ftp. and now the xbox runs as before!

hurray!

ps.
Chancer -> when burning an image in nero it gives you the option to check or uncheck the finalize disk box. at least if you're burning an foreign image. and i used imgburn, magiciso and nero when trying to burn all of the discs that are now useless except from throwing between friends on the beach.
and again, thanks to you all for brainstorming!