hidserv.exe is the windows human interface device service. It monitors your system for when you plug various USB devices in. More information can be found here.

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Microsoft? Windows??98 and later versions provide built-in support for devices compliant with the USB Device Class Definition for Audio Devices, Version 1.0 (see http://www.usb.org/?), and for audio control devices compliant with the USB Device Class Definition for Human Interface Devices (HID), Version 1.0 and 1.1.