Connect your instruments and microphones to the ports on the front of your 1641. Plug microphones into the 1641's XLR ports, and plug your guitar's into the 1/4 inch.
Plug the connector end of the 1641's guitar cable into the power port on the back of the Tascam, and then plug the power cable into a power outlet. Press the "Power" button on the front of the 164.
Install your 1641's drivers before connecting the device to your computer. Download a copy of the drivers if you don't have the 1641's installation disk. Connect your 1641 to your computer via the 1641's USB cable when prompted by the installation wizard. Continue to the end of the wizard.
Install Native Instrument's Guitar Rig software, and then launch the program. The "Windows Vista/XP" setup menu appears. Select "Asio" from the "Driver" menu box. Select the "US-1641" option from the "Device" menu box.