Dell Inspiron 15r Touchscreen stops working for half to 2 days recently

Had my laptop since Dec 2013, always did all updates and ran Dell SupportAssist as it desire and also from time to time.

I'd often check for malware and spyware.

Recently I've found touchscreen to stop working.

When this happens "Human Interface" disappears from Device Manger and "Pen and Touch are not present in CP.

Why would this be?

Thanks in advance,

dvtrv