Two types of redistributable installations for
framework 4.5 are available:
1. Web installer (requires internet connection)
2. Offline installer
These can be found on:
Installing the .NET Framework[
^]
I would not recommend using the offline installer however, the web installer seems to do a better job to install missing parts.
In the past when running a .NET framework application it would automatically check for the presence of the .NET framework and show a dialog offering to download it if not found, sadly this functionality seems to be gone in recent versions (at least in my opinion, correct me if I'm wrong).