Excellent find! I came across the same problem and was looking for a fix. Touch screen was not responding to any touch input as described unless rebooted, powered off etc.

Unchecking the turn off to save power option on "USB Input Device" immediately re-enabled the touch screen again.

What was strange is it appeared it had stored the touch command I tried (Pressing of Start Menu icon) when it wasn't functioning in memory, because as soon as I changed the above setting in Device Manager, the Start menu popped up. So perhaps a driver issue is at play here.

The general problem however might not be just be a simple setting issue though, could be more to it, however your workaround is great! Dell should take note of this, as I'm sure more owners of the new XPS 15 will come across this.

Have you observed any drastic battery consumption issues since performing this change? I've only just done it so I can't really gauge it, but as its a power related setting we've disabled, I'm curious!

Indeed - after using it on battery for a while, it does probably take an hour off your total usage...  I went from a 9 hour average to about 7.5 or 8 average...  95% after browsing the web for about 40 minutes...  

Really isn't terrible when you have a fully functioning computer.

I've only been running it a day - but I can imagine its a little more battery thirsty now, i'd rather have a fully working touch screen though...  lol

Of course. Thanks for the workaround!

Its something Dell need to look into though regardless. Trading battery life for a function that should already work isn't acceptable. I haven't however noticed any specific drivers or software provided by Dell related to the touch screen, makes me think it could be an upstream issue with Windows 8.1 itself.

Power Management looks to be the area of interest as proven with your workaround.

Interesting stuff, thanks for posting your findings. I would agree, I can certainly live with the battery life loss, for a reliable touch screen!

This was a very good thread for me also I have Inspiron 3521 and had the same issue of touch screen stop working. I think it has to do with drivers as noted previously because my issue started after an update relating to ""Intel Corporation - Storage Controler - Intel(R) 7 Series Chipset Family SATA AHCI Controler"" which I think involves the intel HD graphics installed on my system.

Works for my Dell XPS 15 laptop, great thank you!  Dell ... you should really fix this.

Absolutely wonderful. Your trick worked! Thank you so much for posting such a helpful and out-of-the-box fix.Honestly, I cannot remember the last time I found the solution to a strange problem so quick.

*******UPDATE - I had my system replaced and for some reason even with these modifications I was starting to have the screen problems again (after a long time perfect performance)...  SO - just to be safe, go back in to the device manager and turn off those same power management settings under "universal serial bus controllers"

The ones for mine (with all external devices disconnected) were Both "Generic USB Hub" and all 3 "USB Root Hub" devices (Including USB Root Hub xHCI)...  it ended up being all of them.

To reiterate, I disabled the power management on the internal USB hubs that power the mouse, keyboard and likely the touch input part of the screen.  

SO FAR - I have had no further problems...  I had to sacrifice some battery life, but I no longer am poking my screen to death in anger.  lol

This post is in regards to the BIOS/UEFI update A03 that is released on Dells driver and update page.

I flashed this firmware update thinking it would be better, obviously the higher version number, however, you will notice that upon upgrading, you will notice that your touchscreen will no longer work. I spent almost 2 hours deducing what could have been the issue after I had updated some other drivers from Dell and Intel as well. I began combing through the logs in Windows 8.1 and noticed there were problems loading drivers for the NFC and the Touchscreen. So, I began uninstalling update by update until I decided to boot into my Linux OS to determine whether the problem was a driver issue with Windows, or a system wide problem.

Sure enough, I booted Linux, touched the screen and nothing...so I naturally went back to the Dell website to look for the A02 version of the BIOS/UEFI update to downgrade. Couldn't find it, so I searched on my best friend, google, and found a link for the old A02 (current version), and downloaded it. I then began the installation, it will tell you that Dell doesn't like to downgrade, but I ignored it since the upgrade process didn't clear the entire ROM just a portion, plus the EC. So, once I downgraded and reboot, touch screen works!

I hope that helps those who did the same thing as I did.