I'm running out of space on my existing DRIVE (Seagate 80Gb 'Barracuda 7200.7' model ST380011A, ultra DMA) and so bought a WD 160Gb PATA (cheap being the preferable option before total upgrade). Followed steps in an 'upgrades' magazine but computer wouldn't boot. Noticed for the 1st time that with the new drive unplugged, existing drive is recognised as slave whether it is on the end or middle connector.

First ATTEMPT to boot was with existing drive on end connector, jumper to master and new drive on middle connector jumper to slave. This combo wouldn't boot (existing drive STILL recognised as slave).

Second attempt to boot was same connector combo but with both jumpers on 'cable select'. Same result.
Am I wasting my time (and money)?

System: Pentium 4, ASUS P4S800-MX motherboard, Windows XP, 1Gb RAM

Q1. Are the drives compatible?
Q2. If so, which combo is correct?
Q3. Do I need to change something in the BIOS?1.  IDE Cable.  Make sure you're not using the "old" 40-wire 40-pin connector cable.  To support the higher tranfer rates, the newer IDE drives need the 80-wire 40-pin connector cable.
     a.  Is your IDE cable 80-wire with 40-pin connectors?
     b.  Does cable have blue, grey, and black connectors?

2.  Reference(s):
     a.  ST380011A Jumper Settings
     b.  WDC Jumper Settings
     c.  http://www.mikeshardware.com/howtos/howto_connect_ide_hd.html

3.  Recommendation.  I'd work with just the "master" drive until your system acknowledges that configuration.  No point introducing the "slave" if it can't correctly pick up the "master".
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Q1.  Don't know if they're compatible...  However, I'd be surprised if they weren't (as they're two major drive manufacturers).

Q2.  Correct positions on an 80-wire 40-pin connector cable.  I'd explicitly jumper them to "master" and "slave" settings (as all components involved must support "cable select" before you can use it).
     a.  Master/Slave jumpers:
          (1)  Blue connector to primary IDE port on motherboard (lowest numbered IDE port).
          (2)  Grey connector to drive explicitly jumpered as "slave".
          (3)  Black connector to drive explicitly jumpered as "master".

     b.  Cable Select (both drives jumpered for cable select):
          (1)  Blue connector to primary IDE port on motherboard.
          (2)  Grey connector to "slave" drive.
          (3)  Black connector to "master" drive.

Q3.  I'm not aware of any BIOS settings that explicitly affect "master/slave" detection.Also some drives have a "master w'slave present" jumper setting which should be used if you are using the 2nd HDD.

And i agree with dahlerbear...work on getting the primary drive recognised by itself....the BIOS is easily confused. Try unplugging from the wall for 5 mins...hook up only the primary drive jumpered as master and give it power...Thanks for the replies. Had another go at it and realised... had the Jumper diagram Upside Down on the master. Oops, lucky the magic smoke didn't get out. Let that be a lesson to me - DOUBLE check your work.

Jumpered master/slave, and correct connector positions, checked the BIOS and whalla, BIOS on autodetect did the work for me. I love computers! Can't wait to build my own system... when I get some time.Good news indeed...