Original XP disc; for what Computer please, Make/Model? Or was it a boxed-retail Microsoft Windows XP disc?
It is both possible to make an ISO file from your original Windows XP disk (if it's LEGIT!), as well as a bootable flash drive version. As Bass said, you could try Rufus; but that did
NOT work for me, either on XP or Win7 or Win8. I've tried all the USB bootable programs including the ones from Microsoft. They do
NOT work. The only tool that worked for me is WiNToBootIC; you can google it. I've also done it using a Dell Studio540
Vista RECOVERY disc onto a flash drive, and that works too.

That's my personal computer.
Bass is mostly correct, Microsoft has scrubbed about 98% of the Internet of Win7 images, but not XP; those are readily available for free. And as Pauli astutely notes; it's a risky OS to continue using, esecially if you plan on doing any online banking or any online Credit Card purchases.

As long as you don't do any of that, it's somewhat safe to use. *not completely safe*.
Here's a couple of sites to download good XP ISO image files from for use in creating your USB bootable flash drive XP:
http://www.heidoc.net/joomla/technology-science/microsoft/14-windows-7-direct-download-links#
http://forums.mydigitallife.info/threads/17843-Windows-XP-PRO-SP3-SP2-OEM-CDs-32-bit-64-bit Both of these links I have used in the last several months; however, Microsoft reserves the right to pull these from websites with legal action if necessary, so they may not be available when you go there, but it's free so worth a try. If these 2 don't work post back and I'll see if I can find you any others.
And, as a bonus, here's the link for the
WiNToBootIC bootable flash drive maker tool:
http://www.wintobootic.com/ If you get no love from any of these, it's quite likely that the hard drive in your computer has failed. Since you have an XP computer, it is at least 8-13 years old now. Hard drives in PCs are only good for 5 years (25,000 usage hours) and in Laptops only 3 years (15,000 usage hours). So, unless you've replaced that Hard Drive in the last 5 years, it's highly likely to have failed.

This failure will definitely keep XP from installing whether you are running a CD/DVD or bootable flash drive install media.
I suggest that you run a tests on your hard drive. First download the free
SEATOOLS drive test program from seagate.com and create a boot test disc. The
SEATOOLS program is in ISO file format, so you will need to download the free
IMGburn program to burn the
SEATOOLS ISO file onto a blank CD or DVD disc. Once you do this, you may wish to test it on another working computer. Change the boot order preference on your machine to boot from your CD/DVD drive and run the
SEATOOLS program. Ensure that you run
BOTH short and long tests. If
SEATOOLS returns any errors, your hard drive has failed and must be replaced.
Set aside that failed drive and do self-data recovery to get any files you want from it or take to your local Computer Pro and pay him to do the recovery for you.
Best of luck and we'll wait for you to post back the Make/Model of this XP computer for us.
<<<BIGBEARJEDI>>>