Hi,

I have a WD2000BB drive on my table. The drive was opened before or at least some one did something with the top head screw. Neverless, the drive makes normal initialization sounds. Finally the drive is ready after about 20-30 sek.

PC3k detects the drive (Caviar Cy32 Family) and suggests to use the drive in the normal mode.
The Drive ID is ok, but when PC3k tries to read the ROM, the IDX Register starts to blink and the drive goes into Busy mode for a while.

Does anyone know, what's the problem with this drive and what can I do with it?

Some tools don't handle properly pre-Royl drives and especially have trouble to read ROM. Why did you read ROM, probably it is OK. It may have some bad sectors, or bad PCB.
If you have data on it, clone it to a healthy drive. After that, you can repair it, run selfscan.