I gutted my wife's 6 year old WIN 98 SE, ASUS P2FB, PIII 450 with a 70G Westerndigital 5,400 RPM drive. Just before the surgery, I put all of the data files she needed on that drive, along with all of the new drivers for the new components.

I installed a ASUS A7N8X - E Deluxe MB, AMD XP2800+, 2 X 512 M Corsair Value DDR3200, TDK 52X CD RW, Lite-on 16X DVD / CD ROM, and a new Western DIgital 80G 7,200 RPM (with 8M Cache), to the remaining ATI AIW Radeon and the Enermax 465 W. PS.

I removed the WD 5,400 RPM drive, put in only the WD 80G 7,200 drive as single master and loaded WIN 2000 (latest SP and all updates), along with the drivers and software (Winzip, MS Office 2000, publishing software ext.) Computer was working great - fast boot - all is good.

so - the 5,400 WAS master to WIN 98 SE and has all the data - formatted as FAT 32. THe 7,200 IS master with WIN 2000 on it and is formatted NTSF.

So I turned it off, changed the jumper on the WD7,200 to Master (not single drive), added in the WD 5,400 and set it's jumper to slave, made sure that the physical location on the ribbon was correct (black connector to master, grey to slave, and fired it up.

At this point it gets interesting, as the 5,400 is the slave, but had been the master, the machine boots up into WIN 98 from the slave? I tried using all of the WD recommended alternative jumper solutions, including the non-recommended ones because I was using WIN 2000. No change. If I take the slave out and rejumper to single master - all is good.

I intended to has the 5,400 as the "data drive, and the 7,200 as the application drive, but now I am stuck with only one HD, and the 5,400 will not boot as the motherboard changes were too dramatic for it to run in the NForce board. The 7,200 is fine but how can I use both? Plus, all the data is on the WIN 98 5,400 that I can not get to.
Sorry for the length, but I was trying to include all details to make it easier to diagnose.
Any and All help is welcome. THX