|You're on the same workgroup, or you wouldn't be sharing the printer, so the problem must be with Win7's permissions.|
You need to go to each folder hierarchy's Properties and allow sharing. Then you need to set Permissions on the Security tab to tell Win7 who you will allow access to that share. But before you can change permissions you need to be the folder's Owner.
If your wife doesn't log in then you need to have Everyone in the Permissions box.
BTW, it sounds like you wife's computer's root drive is shared. That's pretty wide open. Generally it's better to restrict sharing to certain designated folders.
You may need to reboot before the changes take effect.