You did set the jumper on the master to Master and the slave to Slave right?
Masters when used by themselves are normally set to "nothing".
One Drive ::::: or ::_:
Master ::|::
Slave :::|:
This should not upset the Bios POST but will prevent the drives from being recognized.
Next option is the IDE cable is in upside down. Pin 1 on the wrong end. Look at the drive, make sure the red strip matches to pin one on the drive.
Next the power connector may have a pushed back pin. If the drive gets no power it can load down the ide interface and prevent either drive from coming up. Again it shouldn't but...
Since you know the original drive is still good put JUST the slave drive in and see if the POST completes. It should complete and then say something like no operating system found insert CD removable driver etc.
If the system boots that far ok put in a windows CD or the drives install cd or floppy and format and partition the drive.
It could be the PSU but unlikely for just an additional HD. Disconnect the CD, DVD, case lighting, extra case fans, unneeded USB peripherals etc.
If you have done all this it's RMA time.