Error pop-ups stating "Realtek Network Controller not found."
Before you run any fix, note that RTK_NIC_DRIVER_INSTALLER.sfx.exe to disguise their payload. Several independent antivirus scans have flagged the file as containing Trojan.MulDrop or Trojan.Win32.MulDrop6.DSAH . A virtual CD‑ROM labelled RTL_UL that appears out of nowhere is another strong sign of infection.
Look for ms_rt640x64 – indicates Realtek NIC service installed.