Download and install the Vista drivers (32 or 64 bit depending on your OS). From there, try to manually install the printer through Windows. Again,
not sure if that will work with a dell or not.
Vista
32-bit Drivers
Vista 64-bit Drivers
From Dell.com they doesn't Add the windows 7 Driver which is Not Compatible with Windows 7.
Regards,
MCP | MCTS | MCITP