Usually a scanner comes with extra software, and the procedure usually is install the software first before connecting the scanner to the USB port, although it may vary from model to model.
Try this. Connect your scanner. Then go to Device Manager, find the problematic item and uninstall it. Remove scanner from USB connection. Then restart computer.
Back in 98, if you have installed the scanner software already, uninstall the software completely. Restart.
Back in 98, reinstall the software. Restart if necessary. Then connect the scanner, see if it works.
If it doesn't work, or if you've tried, tell us the brand and model name of your scanner, and someone else might be able to givemore specific help.