C:\SYSTEM.SAV filled with suspicious files. Can I delete this folder?

Some Google searches found that this is used by the HP Recovery Manager (see versions: Windows Vista, Windows 7, Windows 8, Windows 10). The Netflix/Amazon/etc. files may actually refer to the out-of-the-box "bloatware" that the system shipped with. The oldest of my laptops, an HP Pavilion dv6z-3000, had this folder at one point (and IIRC was created when I ran recovery on it).

From what I can tell, the recovery software uses a recovery partition, and this folder is created during the recovery process. It is probably not malicious, though you might want to scan it to make sure it hasn't been infected. I'm not sure if deleting it will break the recovery, but you can try compressing it into an archive and removing the folder to save space.