The thread discusses a user experiencing a mysterious "setup" and "downloader" window appearing briefly during Windows startup, which is difficult to identify and persists despite troubleshooting. Multiple users suggest checking Task Manager, Windows Event Viewer, and startup items, with the original poster noting an Event Viewer error related to SetupARservice, possibly linked to Realtek and audio enhancement software. Eventually, the user discovers Avast detects the issue as a threat in the temp folder, and after disabling unwanted Skype-related tasks, the problem seems resolved, highlighting the importance of cleaning temporary files and monitoring unexpected startup activities.