1.Restart your computer if you haven't done so already.

There is always the slim chance that the Code 28 error you're seeing in Device Manager was caused by a fluke with Device Manager or in your BIOS. If that's the case, a reboot might fix the Code 28.

2.Did you install a device or make a change in Device Manager just before you noticed the Code 28? If so, it's very possible that the change you made caused the Code 28 error.

Undo the change, restart your PC, and then check again for the Code 28 error.

Depending on the changes you made, some solutions might include:

-Remove or reconfigure the newly installed device.
-Roll back the driver to the version prior to your update.
-Use System Restore to undo recent Device Manager changes.

3.Update the drivers for the device. Installing the latest manufacturer supplied drivers for a device with the Code 28 error is the most likely solution to the problem.

Important: Make sure you install the drivers for the correct operating system. For example, if you're using Windows 7 32-bit, install the drivers designed for that specific version of Windows. Many Code 28 errors are caused by attempting to install the wrong drivers for a device.
4.Install the latest Windows service pack. Microsoft regularly releases service packs and other patches for their operating systems, one of which may contain a fix for the cause of the Code 28 error.

Note: I do know that certain service packs for Windows Vista and Windows 2000 have contained specific fixes for some instances of the Code 28 error in Device Manager.

5.Replace the hardware. As a last resort, you may need to replace the hardware that has the Code 28 error.