Help with Windows sharing on Tiger

I have a Mac mini running MacOS X (version 10.4.6), a Windows XP
laptop, and a Linksys Wireless-B router connecting them. The Mac is
connected to the router by Ethernet cable, the laptop by Wi-Fi. There
is a printer (HP Officejet 5610) connected to the Mac via a USB port,
and it works fine when printing from the Mac. I am now trying to share
it with the Windows laptop. Unfortunately, MacOS does not seem to
cooperate.

I enabled the printer for sharing on the Mac (under Print & Fax
preferences), I've enabled Windows Sharing under Sharing Preferences,
I've turned my account on for Windows Sharing, and I've even turned off
the MacOS firewall. But when I run the Add Printer Wizard on Windows,
it doesn't see the printer. It sees the Mac in the workgroup, but no
printers attached to it.

What's more, I cannot access the Mac from Windows Explorer in any of
the several ways I tried. When I click on "View workgroup computers"
in My Network Places, I see the Mac, but clicking on it gives me the
"network path not found" error. MacOS tells me in Sharing Preferences
that "Windows users can access your computer at
\\<mac.ip.address>\<my-username>." But this is not working: when I
click Start->Run in Windows and enter this address, I also get "network
path not found." The same happens when I run "\\<mac.ip.address" or
"\\<mac.workgroup.name>" or "\\<mac.workgroup.name>\<my-username>." I
suspect there is a problem with SMB sharing in general (thus posting to
comp.sys.mac.comm).

I'm out of ideas for how to make this work. Can anyone offer any
insights? I'm sure there's a little thing somewhere that I'm missing,
but I can't figure out what it is.