DELL A860 NON RESPONSIVE USBPORTS

[MEK007]

Hello..
Now i have been working on a dell vostro a860 with a pair of usb ports that are non responsive in windows.
Now the ports will only function when i boot up the system while the desired usb devices are plugged in (mouse , flash drive etc) and windows will allow me access to them ....but as soon as i unplug and try to re insert the drive there is no sigN of any activity not even in device manager
any ideas will be very much appreciated
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mek