Processor Intel Celeron D
Ram 780 mb
Had disk 500gb updated sata
Lg cd/DVD writer
I don't know software programming can install a cd, so make it simple. Please do help I don't want to put away a PC which works well Thank you
The main branch of Ubuntu will run in the hardware you have listed. However it will feel rather slow.
My suggestion is to run Lubuntu or Xubuntu, these two variants of Ubuntu requires less resources, and you'll have a better experience.
The main branch of Ubuntu 14.04 by default comes with Unity user interface (optionally you can get it with the Gnome user interface), both of these will work in your old machine, but it will feel very slow, not recommended.
Xubuntu 14.04 is the same as Ubuntu, but running XFCE user interface (like WinXP), it's less fancy looking than Unity, but it does the job well, still very customizable, Xubuntu is a good medium ground between fancy Ubuntu and dry Lubuntu, it should run smooth enough on that old hardware.
Lubuntu 14.04 uses the LXDE user interface (like Win95) is even leaner and lighter than Xubuntu, it works well even on 486 machines, so if Xubuntu feel slow for you, you can try Lubuntu.
I usually salvage old machines to donate them for people that needs it, and I put Xubuntu on Pentium 2 to early generation of Pentium 4 machines, Lubuntu on 486 and Pentium 1 machines, any AMD/Intel machine built after Pentium 4 generation tends to runs well on the main branch of Ubuntu.
Make sure to get the i386 version of the CD ISO instead of the AMD64.