Unable to access MBL on XP Pro with domain name

I’m unable to access a mapped drive on my work XP Pro laptop with domain name after  a reboot.  A little background -  I sucessfully mapped the X drive to the public share on the MBL.  I also mapped the Z drive to a private share after creating a new user and password.  I can access both drives until I reboot the XP Pro laptop.  The laptop has a work domain name instead of a network workgroup.  After logging in, I am unable to access the network drives.  When I click on both mapped drives in Windows Explorer, I get a login screen that say “Incorrect password or unknow user name for  \\public  The login screen prompt shows the username “domainname\username” with the password blank.  I enter the password associated with my username but it does not work.  I delete the domain name from the log in screen and just enter the user name and password and it still does not work.  Does anyone know how to fix this problem?  Thanks in advance.

Try using the same workgroup name for your laptop and the my book.