Windows security policies dictate that to share a folder properly, a password must be applied to the account that you are using to share with. If you have a user account on your Windows PC that does NOT require a password to login (even it is 'none' for the password, such as with the guest account), then you won't be able to use this account to access the folder.
An account (username) that is sharing the folder MUST have a password enabled on the account or the shared folder will not be able to be seen by others.