If you rest your PC you will loose your file but only your C drive (System file)all setting ,document s,Download so save your all data onto other drive. Make sure you do a thorough backup and have your reinstall discs.
Usually Windows 10 lets you choose between removing and keeping your files when resetting a pc. All your personalized settings will be cleared and OS will be re installed.
If by "power reset" you mean unplugging the power and holding down the power button for 30 seconds, NO that will not delete any files. This document will explain how to perform a power reset on an HP... https://support.hp.com/us-en/document/c01684768
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