I have a wireless network printer. Windows XP, Windows Vista and Mac OS X all cope with the fact that the printer has a dynamically allocated IP address. They find the printer on the network, and send output to it, with no problems.
Windows 7 doesn't. If the printer doesn't keep its IP address (as it is unlikely to, with about nine or ten devices all of which use the network and a somewhat flaky router/modem setup which needs resetting several times a day), the print spooler just quietly sits on the document, waiting for a printer to pop back up in that place.
Now, the whole point about dynamic allocation of IP addresses is that it means you don't need network administration - the whole thing is done automatically. That was a step forwards.
I had a quick scout around for some ideas about a fix. I found two, on forums.
1) Delete the "old printer" on the network, search the network and add the new one. In other words, pretend that the dynamic wireless network is just a misbehaving static network.
2) Configure the printer with a static IP address. In other words, pretend that DHCP never happened, and we're back with static networks again.
I can add another suggestion. Don't bother deleting printers. Add identical printers at every valid IP address, then the computer is bound to find one when you ask it to print.
The third option was tongue in cheek, in case you couldn't tell. And really, the first two ought to be as well. If there's no way around this in Windows 7, and I can think of no good reason - security, technical, protocol - why there shouldn't be, then the newest operating system on the block has tidily made one of the more useful features of dynamic networking unavailable. Nice one!