Printing problem in Win 7
I feel for you.
I can't offer you much immediate help. But maybe this will be helpful over the longer term and useful to others who may read this thread.
I spent several years struggling with printer sharing. After trying lots of pseudo random stuff, I'd get it working. And a few weeks later it would inexplicably stop. It drove me nuts. I thought things had improved at Win 7 but I'm not entirely surprised to hear someone is having all of those same old frustrations.
In any event, one of the best things I ever did was to ditch printer sharing completely. I will never buy a printer that doesn't have an Ethernet port. Put the printer on the LAN. Then you can print from any computer on your network including those connected via WiFi. You will need to install the printer driver on each machine. But after that it just works and, more importantly, stays working.
All of those old problems just went away, permanently, and I was magically transported to printer heaven!