Pop-up Child page from Parent page

Create a form which gets the required info from the user - call it frmCompanyDetail for example.
Add an OK and an Cancel button, and in the designer set these properties:
Form:

StartPosition   CenterParent
ShowInTaskbar   False
AcceptButton    Your OK button
CancelButton    Your Cancel Button

OK Button:

DialogResult    OK

Cancel Button:

DialogResult    Cancel

And add the relevant Properties to your form to transfer the information.

In your Parent page, add this code:

frmCompanyDetail nc = new frmCompanyDetail();
if (nc.ShowDialog() == DialogResult.OK)
   {
   // Use nc properties to retrieve the data and save to the DB
   ...
   }

If you do it like this, and implement the proiperties to transfer the info to and from the form controls, you can also use the same frmCompanyDetail to display and / or change company information later.