If you use Windows 7 and LibreOffice 7.1 doesn't start there, then possibly you have Windows 7 without update. For fixing that issue please install Windows 7 update as it wrote in LibreOffice 7.1 Release Note:
Because of updated Python's change bpo-36085, LibreOffice now requires KB2533623 on Windows 7. The mentioned update is not directly available from Microsoft anymore, but KB3063858 (32-bit / 64-bit) may be used, that superseded the older one (details in tdf#144902).