The ASUS ZenBook UX305 (including UX305CA, UX305FA, UX305LA, and UX305UA) is a fanless ultrabook that relies on correct drivers for stability, battery life, and feature support.
Before reinstalling Windows, back up your existing drivers with a free tool like Double Driver (portable). This provides a fallback if ASUS has removed older drivers for your exact model. asus ux305 drivers