Are the Dell 720 photo printer and a Xerox Docuprint p8 incompatible?

I have a Dell 720 photo printer and a Xerox Docuprint p8, using Win XP, SP2.  I keep sending documents to my P8 but nothing is printing. In Control Panel, the P8 looks installed. I downloaded the latest drivers from Xerox.  Xerox tells me to "completely remove the other devices driver files from the PC, preferably using the other device's uninstall program.
- Ensure that all unneccessary printer drivers (from previous printers) have been uninstalled. Do not simply delete them from the printers window. Use the vendors uninstall program, if you are unsure of where it is located contact that vendor."
This computer used to have both printers working and networked until I had to format the hard drive, so I don't think it is the PC or cable's fault.
 
It also says "Other peripheral devices mapped to the same LPT parallel port where the Xerox printer is mapped" to will cause this. "Remove any of these devices from that port." Xerox docuprint p8 is a LPT1 parallel port printer. The Dell is USB, so I don't think this applies.

I tried the uninstall program for the Dell, but that didn't help. I even restarted a couple times with it uninstalled, but that didn't help either.

Also, the Dell feeds multiple pages instead of one, so I have to feed it one sheet at a time. How do I fix this?

What should I try next to get my P8 to work? Are the Dell 720 photo printer and a Xerox Docuprint p8 incompatible?

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