I had the exact same problem ... and investigated spooler settings, print prefs (took it off auto paper, best printing etc), took it off the PC & tried printing from the the memory card (so not several things there). The HP diagnostics testing software I downloaded said it was working fine. I also changed the B&W cartridge .... but I found out eventually it was actually the colour cartridge! Hooray!
I hope this helps someone else.
madmags, August 2008