Re: Vista Is Still Plagued by Incompatibilities
There is a significant difference in that the Laserjet uses the same technology as in xerox copiers with toner fused to the paper, and the Officejet 7310 use small ink cartridges.
After reading your post on duplexing, I retrieved the duplex adapter that had been in my Photosmart 8250 and installed it in my Photosmart C6180 All-In-One. (They use the same adapter). I initially had the same problem.
Experimenting around with the settings I found a configuration window to apply the two sided printing module.
The path is convoluted and this is for the C6180, but see if your drivers don't have a similar setting buried somewhere.
Start -> Control Panel -> Printer (Under Hardware & Sound) -> (Double Click on Printer Icon) -> Printer -> Properties -> Device Settings Tab. At this point verify that the duplex unit shows up.
Then click on the General Tab -> Printing Preferences -> Features Tab -> Printer Services (at bottom of window) and then on the Configuration Tab. Under accessories check the box for the Automatic Two Sided Printing Module, then click the APPLY button. Close all windows and reboot. This change won't take effect without a reboot.
Let us know how it comes out.