Western Digital WD 800JB

I have an old DELL DIMENSION 8200 with an existing 40GB WD drive. It is going bad although functional. I bought a WD 800JB 7200 RPM, 8MB Cache as a second drive some time ago (still in box). I have a new XP Pro (OEM) to install on new drive. I want to format new drive install XP and have as master on my machine with old drive as slave. How do I do? Shall I just format new drive alone, install XP and all programs and then install old drive as slave? What do I need to do specifically in order for both drives to work as a DUAL HD system? THANKS-need ASAP.

Your plan sounds good to me, although there is no need to install the new drive on its own. However, doing it that way will prevent you from inadvertently initialising and formatting the wrong drive.

To ensure that Windows sees both drives, make sure that both are enabled in the BIOS. Other that that, there is nothing more to do. Windows will automatically recognise any installed drives.