The primary reason for the scarcity of the is the shift in operating system architecture. This camera was manufactured during the dominance of Windows XP and Windows Vista. The drivers were written for 32-bit systems and kernel architectures that modern 64-bit versions of Windows have largely abandoned for security and stability reasons.
One of the biggest hurdles in sourcing this driver is that "Quantum" is a rebranding company. They did not manufacture the internal sensor chip. The QHM 480 LM likely utilizes a generic chipset, often manufactured by companies like Vimicro (ZC0301PL) or Sonix. quantum pc camera qhm 480 lm driver