joytime365, I am sorry, but this link does not apply to the question that you asked or the information you supplied to us....
How do I get win xp home off my computer and format c drive. I want to put in a different operating system. I have a dell, with only a re-installation disk not a original xp disk....how I would go about installing linux/unix.My computer won't run the downloaded iso images.
The link you provided has absolutely no information concerning installing linux/unix.

 You really need to read each and every bit of info on the link and they do not apply to your question at all.

 These are instructions only for persons who have or would like to;
.... upgraded to XP from Windows Me or Windows 98
....a dual-boot configuration with Windows 2000/XP/2003 and 98
....install Windows 98 after Windows XP (You must have a second hard disk or partition formatted for FAT16/32 in order to be able to install Windows 98/Me.)
....customize a new Windows XP installation
....use Group Policy to deploy Windows XP in a Windows 2000 network
....change the default location of the i386 folder
....install Hebrew on XP or 2000
....install XP Pro
....install Windows 2000 Server
And several other instructional links, but no where in this link are there any instructions concerning the installation of Linux on a computer which has XP installed for that you need to go to Linux links.

Your reason given for the removal of XP was that the computer could not "run downloaded iso images". This really has NOTHING to do with XP itself. You do need to use something like Virtual CD-ROM Control Panel for Windows XP(Free) or ISO Buster or Daemon Tools in order to extract the files from an image file to a temporary folder on your hard drive, then run setup to install the program you want.
Though I am not that familiar with Linux I believe it may have the capability to mount and run an ISO built in though I believe you have to create a mount point to do so and since you didn't seem to be aware that you need a tool to use with XP or other os's to run an ISO image then I wouldn't recommend you try using Linux either, only because your research on the original problem or question is flawed.

Frankly, it is my opinion that this is a very poor reason to completely change a computer's operating system, just to be able to run a downloaded iso image when what you need is an additional program to do so but the best way is to burn it to a cd first and then run it.

If the ISO image you wish to run IS Linux then why not go to the Linux.org page and read EVERYTHING they say? One thing recommended is TRY it out before installing. They have links to these try out ISO images...try out being the key phrase here...you don't have to install, you can try it and see if you like it....
All you need to do is burn it to a CD or DVD and boot your machine.
Note it says BURN it to a CD, it does not say RUN the ISO that as downloaded.
Now if these ISO images you want to run are NOT ones of the Linux operating sytem but ISO's obtained via P2P then this is something we do not recommend or support for obvious reasons.... piracy, the high chance of computer infection, etc.