ASP.net Project modifications

I have a login page that detects the remote computers mac address and automatically logs in. I also have a login page that requires the user to input a code. Right now these are 2 different versions of code and I want to make it into one. When a computer from outside the network accesses the page the mac id shows as 000000000000 in the text box. If this is the value then the text box should clear and wait for the user to enter in the number, once done is pressed it should log in. I will demonstrate this. All work must be done via teamviewer. Needs to be completed immediately.