This does not pertain to OP's situation with two SATA drives, but let me correct something TheViper said. He said if you're putting an older IDE (PATA) drive in, set and wire it to be a Slave. Generally that is wrong!
There is no such thing as one Master drive in a whole computer, nor a bunch of Slaves. The Master and Slave designation are merely ways to differentiate two drives that share one port and cable in an IDE system. They are relevant ONLY to that one IDE port they share. EVERY IDE port can have up to two devices (as long as you have a cable with 3 connectors on it). If it is used at all, an IDE port MUST have a Master (set via jumpers on the drive) and it should be plugged into the END connector on the cable. (Sometimes the jumpers need to be set differently depending on whether this is the Master with No Slave, or Master With Slave Present.) IF that port already has a Master device, then the second device MUST be set to Slave, and should be plugged into the middle connector. Exception: you CAN set BOTH devices to "CS" for Cable Select, and then the END device will be the Master.
So, completely independent of any SATA drives you have, if you are putting the ONLY IDE drive on an IDE port, it MUST be the Master of that port. IF the port already has a device that is Master, make the second one a Slave (AND check whether the current Master needs its jumpers changed to allow for the addition of a Slave that was not there before.) If you decide to add the new drive to a second unused IDE port, then it MUST be the Master of that port.
Also, a good guideline to follow: if you have both optical and HDD units on one IDE port, it is better to make the HDD the Master (on the end of the cable, too) and set the optical unit to Slave. If you add an HDD to an IDE port that already has an optical drive and make this change, also check in Windows Disk Manager what letter names Windows assigns to these devices. It might just give the old name for the optical drive to the new HDD, and give the optical unit a different name. You can manually change those to what you really want (to keep Windows happy when trying to find stuff on the drives) by RIGHT-clicking on a drive in Disk Manager and Changing its Name. Back in BIOS Setup, also check the Boot Priority Sequence to be sure the optical drive you expect to use there is still in the list properly, because you have changed its port identity.