You don't have a WiFi adapter for your PC?
To use USB tethering, you have to set it up in the Settings somewhere so the connection to PC is not charging, but should be data transferring. You probably also need to install LG Mobile driver or PC suite.
LG Software, Firmware, & Drivers Download: Optimize your LG devices by downloading the latest drivers and firmware updates. Keep your LG products up-to-date.
www.lg.com
As ch33 has suggested, you shouldn't use smartphone hotspot for multiple devices (or a long term) solution. Constantly use smartphone as a hotspot will shorten its life since your phone probably become very hot.