THE FOLLOWING IS COURTESY OF MICROSOFT Help and Support
When you plug a USB device into a Windows XP-based computer immediately after the computer comes out of standby (S3) or hibernate (S4), the computer may not recognize the USB device. When this issue occurs, the USB device may be listed in Device Manager as an unknown device, and you may receive the following warning message:
Unrecognized device has been found.
This issue occurs because, when the computer comes out of S3 or S4, there is a five- to ten-second period when the selective suspend feature of the USB driver will interfere with detection of a new USB device connection. The time period depends on several factors. This includes the following factors:• Host controller hardware
• Attached hubs
• Attached devices
• USB driver versions
• Support for USB 2.0
• Additional system hardware or configurations that may change the timing
There may be other reasons that a USB device is not detected
After the computer comes out of S3 or S4, wait five to ten seconds before you plug the USB device into the computer or hub.
After the computer comes out of S3 or S4, unplug the USB device, and then plug the device back into the computer or hub.
Use the Device Manager to scan for new hardware. Follow these steps: 1. Click Start, click Run, type Devmgmt.msc, and then click OK..
2. On the Action menu, click Scan for hardware changes. This causes Windows to recognize new devices.
3. Close Device Manager and Control Panel.
Disable power management of the USB hub.
Note If you perform the following procedure, you may also reduce the battery life on a portable computer.
To disable power management on the USB hub, follow these steps: 1. Click Start, click Run, type devmgmt.msc, and then click OK.
2. Expand the Universal Serial Bus controllers node, and then follow these steps for each USB Root Hub that is listed: a. Right-click the USB Root Hub, and then click Properties.
b. Click the Power Management tab.
c. Click to clear the Allow the computer to turn off this device to save power check box, and then click OK.
SIMILAR PROBLEMS AND SOLUTIONS
For more information about advanced troubleshooting tips for general USB problems, click the following article number to view the article in the Microsoft Knowledge Base:
Advanced troubleshooting tips for general USB problems in Windows XP For more information about how to troubleshoot unknown devices in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
How to troubleshoot unknown devices that are listed in Device Manager in Windows XP
Try restarting the computer with the device in. Sometimes if you clear the memory that might help (stating the machine without memory then put it back and start it again).