We're sorry to hear that the scrolling function of your touch pad stopped working. Was there any change that happened prior to the issue? Where did you check the touch pad driver?
You may try the following steps to verify if the touch pad driver is still on the laptop.
**Go to Devices > click Mouse and Touch pad on the left side > under Related Setting (click on additional mouse options) > the mouse properties windows will show up (look for Device Setting stab) if the tab is missing then the Alps® Pointing Device for VAIO® Driveris not installed. If the tab is present, click on the Settings button (check the appropriate Multifinger Gesture setting that you want) > click on the OK button. Replicate the issue.
You may also reinstall the Alps® Pointing Device for VAIO® Driver (not sure if it will be installed since your laptop is running Windows 10 and this driver is for Windows 7 operating system)
If the issue still persists then this is probably one of the limitations of Windows 10. I'm sure your aware that the model VGN-NW250F has no Windows 10 support from Sony thus you're only using the generic Microsoft drivers.
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