If you are writing in VB.NET, the keywords are
AndAlso
(equivalent to C# double ampersand) and
OrElse
(equivalent to C# double pipe).
If (Form2.txtName.Text ="" OrElse Form2.txtLastName.Text = "" OrElse Form2.cboField.Text = 0 OrElse Form2.cboStudy.Text = 0) Then
MsgBox("Fill all your information please")
End If
You should also use String.IsNullOrEmpty() to check if a string is null or an empty string ("").