The funny thing is that the correct size (250 GB) is displayed in CMOS (BIOS).
I have received some support from the dealer, but this hasn't helped yet. (I have tried different jumpersettings without success.)
I thought maybe someone in this forum could help me out before I eventually return the harddrive to the computer shop and get a new one.
My mainboard is EPOX 4PEA+ with Intel 478 Socket. I hope that there is not a compatibility-problem causing this to happen. (In that case it might be necessary to upgrade the mainboard I suspect.)