Welcome to A.O Maarten,
I agree with the above posters it's probably a faulty or altogether missing HD. The Amiga dosent need a large HD and just a note that if you do get one and its larger then 4 gig you will need a patch and even better yet a different file system in order to use the space over 4 gig. (the amiga OS dose not support drives over that size by default) But a 4 gig drive is plenty of space as the OS needs less then 100mb of space.