Using Old Laptop PC as 2nd Screen for Macbook Pro i7

am just wondering if this could work?

I have a Macbook Pro, and an old PC laptop.

Could I switch the PC laptop so that the screen becomes a 2nd screen for the Macbook? and then maybe switch back?

Can a computer laptop become a 2nd screen?

I have seen Screenrecycler, but not looked into it properly yet - does this need a internet connection? as my old pc has no wifi or modem, but could get internet from the Macbook via an Ethernet cable?