The slave has to be on the IDE connector closest to the motherboard.

Is there any more info you can provide? You *should* be able to connect any 30 GB hard drive to a current computer by slaving it to your master hard drive. I'd say double-check the jumpers, but I'm sure you'd *never* have both jumpered as masters.

Try using Cable Select, maybe. (If your jumpers are labelled, it should say MA, SL, and CS. If you put both on CS, it should automatically read the HDD at the end of your IDE cable as the master and the one in the middle of the cable as your slave.

Also be sure that your IDE cable isn't plugged in backwards. (Upside-down like Unne said *should* be impossible, as any decent IDE cable has a tab on it to prevent that. The red line along one end of the IDE cable goes to pin one. (Pin one is usually on the left-hand side of the IDE port, but it should be labelled in any case)