thanks for your reply.
Yes, except n°1 - empty Temp directory, I had tried/checked all of those.
I emptied the local temp folder tonight, but it still won't work.
Please note: the installation doesn't give me any problem. The program was working fine, until at one point *plouf* it stopped working. I can re-install it without any problem, it just crashes when opening.
\\edit\\ I seem to have located the problem, it's in the library files. If I re-install iTunes without my library, it works fine (though there is no music in it, yet). As soon as I import my library, or replace the My Music\iTunes folder with the old one, it stops working.
Ok, getting closer to the source of the problem...
1) starting iTunes with an empty library: OK
2) starting iTunes with my library imported, but with the external drive containing the actual music deactivated: OK
3) starting iTunes with my library, and the external drive containing the actual music connected: BUG!
So iTunes suddenly doesn't recognise the hard drive, or recognises it but crashes trying to read it.
Looking at the processes, iTunes goes up to using 15% of my CPU before crashing. To compare: Firefox with 4 tabs open, including a streaming video, only takes about 0,4%...
Ok, it seems to be working for the moment.
While "re-ordering" my library, iTunes has changed a bunch of file names from Greek/Arabic/Russian to incomprehensible chatter. I renamed the files by hand, one by one (took me over three hours), giving them their original name, and iTunes seems to be functionning again.
I was lucky to be able to locate all of them...
Subject closed! (for now...)