I have had a painful few days with my Windows 7 print spooler crashing (you can stop the spooler service but can’t restart it) after one print run on a QNAP 239 Pro II shared printer. Lots of rebooting required, which is fairly quick on the Studio XPS, but still a pain.
I have currently improved the situation by deleting the printer (e.g. \\nas\naspr1) and the port set up for it (hint: right click on any other printer in the Devices and Printers window then choose Printer properties>Ports then click on the name of the port, rather than the checkbox, and click Delete port).
Then choose Add a printer from the Devices and Printers window, Add local printer, Create a new port, Local port, and then type \\nas\naspr1, install the relevant driver (I chose replace, just in case) and you should be good.