Hello,<BR>I am working with SDI (Single Document Interface) in VB.NET, What I found is that, it is not same as we did in Visual Basic 6. I want to develop an application which I want it should work as follows.<BR><BR>I have a form for say, login, which asks for userid and password. after validating UserID and password I want to show the main form. so what I am doing is,<BR>in the click event of the associated button I am writing<BR> <BR> .......<BR> .......<BR> Dim mainfrm As New MainForm()<BR> mainfrm.show()<BR> Me.Hide()<BR> .......<BR> .......<BR><BR>Now upto this it is working fine, suppose from the main form I want to click a logout button, which should show the previous form which was kept hidden in the block of code above, How can I do that, Please help me, Thanks