missing eth0

[arne anka]

please, always answer the last message! otherwise your messages are  
completely out of context an there's no thread to follow.

sounds as if you (and your friend) use a monlithic kernel with the module  
built in.
to make sure, do
uname -a
and compare the kernel version number.
additionally you need to give the name of the distribution you are using,  
since i do not know where to find logs, maybe saying something useful.

try
logread
or
dmesg