This would be a question best posted to the scripting newsgroup. However
here is sample code that will change a users password
Setting a New Value for a User Password Using a VBScript Active Server Page
Dim User
Dim UserName
Dim UserDomain
Dim NewPassword
UserDomain = "Target_User_Domain"
UserName = "Target_User_Name"
NewPassword = "New7Pass"
Set User = GetObject("WinNT://" & UserDomain & "/" & UserName & ",user")
Call User.SetPassword(NewPassword)
User.SetInfo
Changing a User Password Using a VBScript Active Server Page
Dim User
Dim UserName
Dim UserDomain
Dim NewPassword
Dim OldPassword
UserDomain = "Target_User_Domain"
UserName = "Target_User_Name"
NewPassword = "New7Pass"
OldPassword = "Old6Pass
Set User = GetObject("WinNT://" & UserDomain & "/" & UserName & ",user")
Call User.ChangePassword(OldPassword, NewPassword)
User.SetInfo