The problem is almost always the security settings on Vista. You should be able to access files, folders, and printers on the Mac from Vista, but it may be tougher to access Vista from the Mac.

To do so, you’ll want to change the LAN Manager password system by

Click “Start → Run.” Then, type in the Run field: “secpol.msc.” That will bring you to Vista’s security policy system. Once there, use “Go to: Local Policies > Security Options” and then find “Network Security: LAN Manager” authentication level. Once there, change the Setting from “Send NTLMv2 response only” to “Send LM & NTLM — use NTLMv2 session security if negotiated.”

or by editing the registry directly:

Using RegEdit find HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\LMCompatibilityLevel and change the default entry from 3 to 1, and save it.