Can’t access boot menu

If you can access the bios then change boot priority to DVD as #1.  Save change in bios, exit bios, restart without unplugging power cord.  In theory that should force old optiplex to boot from XP CD first.

if you still have trouble booting from cd, try replace cmos battery w a new battery and clear cmos settings via motherboard RTCRST jumper.

Along with 2 short beeps

I changed the boot sequence for cd first and after restarting and the dvd drive sounding like it’s reading the disc I left it for 10 mins and nothing happened I was left on a black screen with no error codes for the front

and after getting a new battery and clearing the cmos settings on the board I get a post error again 

That would suggest the XP disc you use (?a burnt copy and not genuine) is not readable or bootable or the dvd drive itself is defective (possibly given age of pc).  If you have spare parts then replace the 330 dvd drive with one that is verified to work in another desktop.  Two beeps may be telling you date and time need to be changed because during battery replacement and cmos clear all old bios settings are erased.  You would need to change boot priority to dvd #1 and save/exit again.

On another computer I am able to confirm the disc drive works and I have a genuine dell windows xp pro sp2 disc