You should be ok to delete the set-up files, but the downloaded program files is a different matter. This depends on the program files downloaded, and whether or not you wish to keep some while deleting others.
What is ransomware and how do I protect my PC from WannaCry?
What I learned from my mentor, Oscar-winning VFX supervisor Phil Tippett
Siri vs Google Assistant
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.