|When using cable select both drives on a cable must be jumpered CS and they are distinguished as separate drives by their position on the cable. The blue connector attaches to the motherboard, the slave attaches to the gray connector (usually the middle connector) and the master to the black connector.|
When using master/slave jumpering well, the drive you want to be master is jumpered as master, slave drive as slave.
Check to see how the drive that's in the computer now is jumpered. It's a compaq computer so it's probably jumpered as cable select (that's how compaq usually does it). Then jumper the drive you want to add accordingly.
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