Win 7 detection problem

I have had a USB-UIRT working fine on a Windows 7 system for some time. Yesterday it stopped working with Girder - Girder reports an error - UIR failed to initialise - Unable to connect to USB-UIRT device! When I look in device manager, it says the device is a Microsoft ehome Infrared Transceiver. If I uninstall and reinstall, Win 7 always detects it as a Microsoft device. I have the latest firmware installed. If I connect to another Win 7 machine, it is detected OK.
Any thoughts or help greatly appreciated.
Nick.
Any thoughts or help greatly appreciated.
Nick.