I had the same issues ghosting to the optiplex 760 model. Ghosting worked after the following steps.
1. Disable achi in the bios.
2. "Repair" Xp your image
3. Install the dell drivers except the intel matrix storage manager and update the bios.
4. Then do what "BobTheTerrible" suggested on the technet forums located here
Do this for both the Hard drive and the DVD-RW
"First download the SATA drivers from Dell. Download
Copy the file onto the computer somewhere like c:\dell\drivers\?
So you turn ATA support on in the BIOS for the SATA controller.
Boot into Safe Mode.
Open Device Manager.
Find the Primary IDE Channel device (there may be 3 listed, I picked the top one)
Right click - Update driver
"No at this time" - Next
"Install from a list or specific location" - Next
"Don't search. I will choose the driver to install" - Next
Click - Have Disk
Browse to the iaStor.inf file - Click Ok
Choose the "Intel(R) ICH10D/D0 SATA AHCI Controller" - Next
Go into the BIOS and enable the AHCI support for the Sata.
5. Then login to windows and it will find "new hardware". You will have to reboot.
6. Sysprep the 760 and you are good to go.