You could try creating a new folder on c: then right clicking on it and sharing it. You get the option to turn off part of the windows firewall that blocks sharing. Now see if after rebooting the roku you can see it. When I open the disk the shared folder has a little hand under it.
I am 90% convinced it is the pc and windows. You are sure that you don;t have any other firewalls like macaffee. As the smbclient didn't see your server.
I believe it is on port 445 and 139.
Also try from the command shell on your pc
net server stop
net server start
and see if rebooting the roku finds the shares,
If you have another pc on your network you can also try to see if the shared folders are visible.
Also when your router was in the loop could you ping www.google.com from the roku command line?
if your computer name is djt1r661 (on my computer properties ) which is mine then I made a shared folder mvpmc and gave it that shared name
then I can mount by hand via
smbmount //djt1r661/mvpmc /mnt/smb/mvpmc -o username=guest
what happens if you try by hand to mount a share?
or try via its ip number rather the the name i.e.
smbmount //192.168.1.101/mvpmc /mnt/smb/mvpmc -o username=guest
both forms mount the folder for me. I think seeing the error might help.
Good luck and I am sure we will figure it out.