You need to select an OS from the list shown by the program (that are all Windows installations it finds on all your hard disks). If there is nothing on the list, it seems something is wrong with your PC.
Why do you want to do a system restore? And why can't you do it from within Windows?
On the system restore option in repair tools on the media usb, it just takes me to a small window that says I need to select an operating system, and that I need to restart the laptop, choose an operating system and go back to system restore. The problem is I don't know how to select an operating system. No options show to choose an operating system before clicking system restore. Can anyone help please?