Many cheap webcams from the mid-2000s used Sonix chipsets. The Quantum QHM 480 LM is rumored to be a rebranded Sonix SN9C201 or SN9C202. You can try the generic Sonix driver.
Right-click the device (it may show as "USB 2.0 PC Camera") and select . Choose Search automatically for drivers . 2. Manual Installation via Driver Files quantum pc camera qhm 480 lm driver