Hi, thanks for your complete reprise of what happened to the phone, well,
I used it today, worked fine again (but the battery I bought off ebay didn't last long (I'll perform a capacity test with a constant current load when I'm done charging it)), now it's charging flawlessly on my PC with another USB to µUSB cable, I'll check the cable you gave me (thanks anyway), it might be the problem of the phone ignoring the battery or saying "charge problem" or shutting down. but with the new cable:
it charges perfectly fine !!!!! so no problem around here.

one more thing: do you know the password for Superuser and the phone pass ?

also, is there some tuning that might make it better running, sometimes firefox is a bit slow or the and animation of screens is lagging, nothing problematic but if you have fixes, I would be very interested.

anyway: the N900 is a wonderful device, I hope from now everything is going to be fine.
Thanks in advance