How to Disable USB Power Management in Windows XP
The default settings for Windows XP cause it to automatically turn off the USB ports to save power after certain actions or a set amount of time. These settings may cause problems when the computer comes out of sleep or hibernation and after long periods of inactivity. These problems include devices not working or USB drives and peripheral devices not being read or recognized when plugged in. Users who experience frequent issues with their USB ports may need to disable this feature if other troubleshooting methods fail to solve the problem.
Open the "Start" menu and click on "Run."
Type "devmgmt.msc" and press the "OK" button.
Open the "Universal Serial Bus controllers" section of the "Device Manager" window.
Right-click on the first entry of the "USB Root Hub" list and select "Properties."
Click the "Power Management" tab and uncheck the check box next to "Allow the computer to turn off this device to save power," then click the "OK" button.
Repeat for each of the "USB Root Hub" entries present in the "Device Manager" list.