how to insert values to uniqueidentifier table in windows form

Question

hi all ...i'am having a problem ..i'm working on an C#.net project ....but the data base Table contain the (unique identifier) type ..and i don't know how to insert the values from Windows form to database. this type ...and also i can't add data to my database coz this type is giving me alot of errors.2 TextBoxs and 1 Button Iam  having in Windows Form.When iam entering the data and click OK button, data is saved but Uniquie Id shows NULL.Its Primary Key Column.it's not auto increment for an id ...plz help ....and thnx in advance