This is an isolation test for an installed ASUS Essence STX II, not a diagnosis based only on random restarts. Record its slot and connections before removal and use the computer’s service procedure.

  • The PC randomly restarted soon after reaching the Windows 11 desktop.
  1. Power off and disconnect AC.
  2. Remove the ASUS Essence STX II sound card.
  3. Reconnect power and start Windows.
  4. Repeat restarts and normal use long enough to test recurrence.

Reported outcome: The topic starter reported nine stable days and roughly 30 restarts after removing the sound card.

Keep the card and its configuration. If the restarts continue, do not attribute the fault to the card; restore the recorded hardware configuration when safe.