Relevant specs:

Windows 7 Pro 64-bit

ASUS M4N78 Pro

Chipset: nVidia GeForce 8300

CPU: AMD Phenom II 945

Mem: 8GB DDR2 800

Details: Replaced MB, CPU, RAM. Booting into BIOS, USB keyboard and mouse detected and function properly. Booted into Windows 7, they stop working.

Device manager shows 4 entries with conflicts:

Standard Dual Channel PCI IDE Controller High Definition Audio Controller Standard OpenHCD USB Host Controller Standard OpenHCD USB Host Controller

ALL OTHER USB DEVICES that I have function properly. HD webcam, Wacom tablet, usb flash drives, usb HDDs (includes SSD drives and other 2.5" and 3.5" types), usb microphone, and many other device types.

ONLY usb keyboard and mouse affected. Three different keyboards, two wired and one wireless usb mice tried but all fail. All of them work on other machines running Win8.1, Win7, and Ubuntu. Fortunately I have a PS/2 keyboard so I can work on this problem...but no PS/2 mouse...lol...Go, Go, keyboard shortcuts!

I find it interesting that only keyboards and mice are affected, given they are still generally the only USB 1.1-based devices still around and these drivers that have conflicts are all based on USB 1.1 technology.

I have uninstalled each of the drivers to see if the OS would correct itself on reboot. All reinstall, but with the same conflict issue. I have disabled and re-enabled Legacy support in the BIOS to no effect. The keyboards and mice not only function fine in BIOS, but the BIOS visibly lists them.

I have installed the latest chipset drivers AND updated the BIOS to the latest firmware.

I am about to TRY to perform a System Restore to a point before I installed the chipset drivers, but I doubt that will work. The initial USB keyboard and mouse I had plugged in weren't working then, either. I will update this IF the System Restore makes any difference.

I have searched and found this issue in many, many places. Things I have found in common with my exact issue that others have: The same devices I have with conflicts others have, we all have nVidia chipsets with Windows 7, although they are different chipsets and different motherboard brands and models. I find it interesting that the conflicted devices are all I/O related, regardless that it seems to affect only USB keyboards and mouses.

This is NOT a Windows 7 USB3 issue! Those particular problems have different device conflicts and seem to mostly affect Intel chipsets, although a few nVidia chipsets with this issue are around and most seem to affect Windows 8.1. This motherboard doesn't have USB3 on it, anyway.

Thanks in advance to everyone who offers any insight.


You replaced the motherboard and did not reinstall W7? Bad idea unless you used sysprep before replacing the drive.

What you can try now,

Important: Use legacy usb 2.0 ports for your mouse and keyboard before doing this.

Back up any documents in your user(s) folder(s) as this procedure may modify the current user(s) account(s).

Open a run box Win+R

type in


this should open the folder location of the sysprep tool, execute sysprep.exe


Configure it like the image below and hit OK, this will remove all hardware drivers and restart, when windows loads it will ask you to set up windows and user accounts then when the desktop appears W7 will load all the proper drivers it has available, this may take some time, then you can install the rest of your motherboard drivers.

enter image description here

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