I'd look at device manager and the event viewer for errors.
What OS? What sort of printer connection?

If the NIC you replaced was integrated, I would disable it in the bios, so that the new NIC would be more likely to use the same interupt etc.

If you still don't get anywhere, I'd remove the NIC temporarily and try printing. Maybe you somehow damaged the printers port when adding the NIC.

>I have an HP DeskJet 840C.
>
>A few days ago, I replace my NIC card. Now, the printer
>no longer prints.
>
>When I attempt to print, I get nothing - no error, no
>printing, nothing.
>
>The print queue dialog show the document as printing, but
>nothing comes out.
>
>It's plugged in and on, and I went to HP.com and updated
>the driver.
>
>I'm stummped.
>
>Help