You will need to open each PC, to remove then install the drive
IDE drives come with jumpers in place set to master. Move the jumper to the Slave position on the new drive. If a jumper did not come with the new drive, take the jumper off M or MA on the first drive (it will still act as Master) and place it on Slave on the second one.
Insert the new drive into a drive bay and screw it in. Do not over-tighten screws into the drive. If you want to put a 3.5" drive into a 5.25" drive bay, get an adapter that holds the drive and fits into the 5.25" bay.
Plug an available four-wire (red-black-black-yellow/orange) power cable into the drive (it only fits one way). If there are no free power cables, get a power cable splitter. Pull out an existing power connection to another drive and insert the splitter. Attach both drives to the splitter.
The connectors on the flat signal cable can be inserted up or down, so be sure to connect the second drive in the same manner as the first. One side of the cable is marked, typically with a red line or pattern of dots. Line that side up with pin 1 on the host adapter and pin 1 on the drives. If the cable isn't long enough, a longer 40-pin IDE ribbon cable can be purchased. The three connectors on the cable are common. Either one can be used for either drive or the host adapter.
Don't think you can split an ISO File
You can see if mywebexpc will install to an XP Home PChttp://www.mywebexpc.com/index.php
This would be the easiest as you just open the desktop of the one with the file, using the new PC, then transfer it