You should first attach the external AC power adapter to the laptop.
Then go here and install the latest BIOS, Intel Chipset, and Dell Power Manager Service. Once all are installed, one at a time restarting after each one, reboot the laptop.
Then read through this Dell article about enabling the Nvidia GeForce Experience WHISPER MODE.
You need to then post a video with audio of the Inspiron 15-7577 with the AC adapter attached allowing us to "hear" the fan. Both on the Windows desktop and while gaming.