If you don't have the disc, do you actually have a licence to use this software? If so, you should be able to download and install using the licence or contact MS for help - if not, you will have to buy one.
Windows defender download from click here.
For the future, if you want to backup these programs, you will need to backup the entire drive - you cannot simply run from the program files without the registry entries.
NB I would not rely on those restore points either. In my experience 90% of the time, when you need them, they don't work.