Password Protected Network Shares In Workgroup

4 computers using broadband connection to internet (easy) 4 computers using workgroup on router and switch to share network shares. The second part let me explain further. I prefer to have Essentially the entire "user files" folder shared to my other computers given they supply a network password....

I cannot access the other computers i type \mainpc i get a typical error "is not available share. Contact the admin for access" My attempts: *all have workgroup the same *all run vista business or ultimate *all can access the internet *reset network connections *reset router even tried using a simple switch only without internet *insured networks were set for PRIVATE network *utilized user name and passwords for all accounts on all computers but the guest account *shared folders using advanced share and pick specific user admin accounts to have full access *i can under network see the computer i want to gain access but it won't ask me for a user name and password if i type \mainpc *I've tried under user accounts in control panel "Manage your network passwords" and inputed the user name nad password on the desired network i want to gain access which semi worked but now it doens't ask for a user name and password. *I've disabled all firewalls and virus scanners *pc 1 and 2 can talk freely to pc 3 but pc 1 and 2 cannot talk to each other.*network discovery on *file sharing on*public folder sharing off *password protected sharing on