Very Computer

You also may be having a problem due to failed logins.
To make it as simple as possible you need to do the following
( Sorry if you have already been through all of this )

A user on the Windows PC needs to have a login name
and password. They should login when asked ( ie not press
escape or click on cancel )
Each user should have the same login name and password
on the linux box.
On the Linux box  you should have run
smbpasswd -a login-name
( where login-name is the same name as above )
and type in the same password as above each time
it is asked for.
best wishes,
norman