Hello JRS,
Most Dell computers from the XP era come from Dell with a customized partition layout. There are two hidden partitions, one which has the Dell on-disc diagnostics and the other which has the Dell recovery partition. The third partition is the
nonhidden C: partition which of course contains the currently installed operating system.
Dell uses its own bootloader to give you a menu from which you choose which partition to load. If you see a blue bar with
www.dell.com at the top of the screen for two seconds during computer startup, after the Dell logo is diplayed bu before the Windows logo is displayed, that means the Dell bootloader is still installed and
if not altered by previous OS installation attempts, could be used to access the hidden partitions. During those two seconds while the blue bar is at the top of the screen, press and hold CTRL, press F11, then release both to access the menu for the
Dell Recovery Partition. To access the diagnostic partition, press F12 right after the computer is powered up to get a one-time boot menu, then from this menu choose the option for the diagnostic partition.