General :: Limit Access To Database To Few Users

I am using Access 2007. My boss has given me a project to create a tool for our team. I'm done with most part of the project, but for the last part I want editing and updating of database restricted to a few members of our team. However others can access the database and run queries etc. through buttons on a form.

I went about creating a login form for users to get access to the database and in turn created a table with fields UserID, UserName, UserPW and a yes/no field titled IsAdmin. For those who would be limited access would log in as 'Other' user and same as password. I am then using the code to determine if the user should be treated as admin or not by looking up the IsAdmin field in the table. Following is what I have so far, but it needs correction some places and I can't figure where:

Private Sub cmdLogin_Click()
Dim xxAdmin As String
'Check to see if data is entered into the UserName combo box
If IsNull(Me.cboUser) Or Me.cboUser = "" Then
MsgBox "You must enter a User Name.", vbOKOnly, "Required Data"

[Code] ....