The driver files were not pre-loaded, or the hardware wizard timed out.
Because Windows XP handles USB driver enumeration differently than modern operating systems, the order of operations matters. Always install the Siemens software before plugging in the hardware. Step 1: Install STEP 7 or Simatic Net Insert your Siemens STEP 7 V5.5 installation media. siemens pc adapter usb a2 driver windows xp