Welcome to Macs and to the forums!
The OEM for the Dell printers is Lexmark - the Dell 924 is really a Lexmark X2350. However, there are no OS X drivers for that printer on Lexmark's website.
A poster in
another forum indicates that he inquired with Lexmark and they don't support the X2350 for the mac (i.e. no driver available). There was a comment that this person sold the printer on eBay and got a supported one.
Lexmark's
Mac Compatibility page indicates that the X3350 has an is Intel-Mac driver, which might give you some functionality with your printer. However, clicking on the driver download page brings up a list of OS's that does
not include OS X, so you may need to go through Lexmark tech support to even try it.
FYI, you are encouraged to mark responses to your questions as Helpful or Solved, if apropriate, as described
here.