When trying to change the port server name (I have a USB printer hooked up to a router) for the network attached printer, you get this message, Windows Port Error: 0x000000aa when trying to change printer properties in Windows 7.  What to do?

First we tried to start and stop the printer spooler service ( Start -> Run -> service ) but that didn't work out.

Lastly, use your trusty regedit from the start menu (Start -> Run -> regedit):

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Print\Monitors\Standard TCP/IP Port\Ports\9100

Change the value of HostName to the new IP. Or, if you know what it is that you are doing, change any of the other values to the one you need.

Cheers,
TK