Calibrate your VPC Device in the VPC Configuration Software by selecting the device in the device list and clicking "LOAD VPC DEVICE". On the "AXIS" page there is a button on the lower right hand side labelled "Calibrate Axes". Follow the on screen instructions and then click "SAVE VPC DEVICE". Do not use Windows to calibrate your VPC device.
After completing the calibration movements on each axis, ensure that you are returning them to the center/neutral position before completing the calibration.
Clear any windows calibration data by clicking on the Start menu and typing "joy.cpl" - open the control panel item. Select the relevant device and click "Properties". On the "Settings" tab, click "Reset to Default". This will ensure there is no Windows calibration data conflicting with the VPC firmware. You can then re-calibrate in the VPC Software.