apostrophes in string for SQL not working

Help: I have tried everything all day and cannot figure this out.
 OK I tested the Insert Statement in MS Access and it works.
INSERT INTO user ([user_login], , [create_date]) VALUES ('user67', 'suesargis@yahoo.com', '11/15/2010 8:18:14 PM';
 
So how do I add the apostrophes in the string below to get the above when using executenonquery.? The string produces everything ok but it is missing the apostrophes.
string querystring = "INSERT INTO user ([user_login], , [create_date]) VALUES ("  + CreateUserWizard1.UserName  + ", " + CreateUserWizard1.Email + ",  " + tbdate +";";



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