Question 1

Install fails or rolls back?

Accepted Answer

Old NEC uPD720101 packages often target XP/Vista or the wrong architecture. Confirm 32/64-bit and OS version; if setup still fails, update manually in Device Manager or use Windows’ built-in USB 2.0 EHCI driver.

Question 2

Controller not detected?

Accepted Answer

Reseat the PCI card, try another slot, and check BIOS settings for PCI/USB legacy support. In Device Manager, scan for hardware changes and look for a yellow warning under Universal Serial Bus controllers.

Question 3

Version conflicts/yellow bang?

Accepted Answer

Remove any existing NEC USB driver, select “Delete the driver software,” reboot, and let Windows reinstall the inbox EHCI driver. Avoid stacking old vendor packages over the Microsoft USB stack.

NEC PCI to USB Enhanced Host Controller uPD720101 Driver