When I boot into Windows, HWinfo64 automatically runs, even though I don't see it in the Startup Apps list or under the Startup tab of Task Manager. This isn't particularly bothersome, but I'm curious why this is so.
This startup is done via Windows Task Scheduler. You can open it and check the HWiNFO task. If you don't wish to auto start HWiNFO you can disable it there or in main HWiNFO settings.