the class installer has denied the request

I have an usb benq scanner s2w4300u and I installed it many times before and

there was no problem at all, last time whn I connected it and was trying to

install it I got failed, I always receive the message "the class installer

has deied the request to install or upgrade this device"

I tried many solutions such as uninstalling all USB drivers, removing all

usb peripherals connected to the PC, installing new drivers for that

scanner,...

I hope to help me

thanks,

Ali El-Matarawy