XPS 8960, won't wake from sleep no matter what

I have exactly the same issue. Pc only a week old.

Is it going to sleep or is it hibernating? 

Open Device Manager and expand list under USB. For every USB device that has a Power Management tab, make sure the box "Allow PC to turn off..." is not checked, and the box to "Allow to wake" is checked. (Not every USB device will have those two options.)

Then repeat the same thing for every Human Interface Device (HID) in Device Manager that has a Power Management tab. (Not every HID device will have those two options.)

If you have an add-in NVidia video card, open NVidia Control Panel and click Manage 3D settings in left pane. Then scroll down right pane to Power Management and set it to "Prefer Max Performance". Save the change.

Reboot when done and test again...

Is this 'new', that is it is been like this since you got the PC or 'new' in that this just started happening?

If 'from day one', what type of mouse and keyboard (space bar or a CTRL key I think will wake it up) do you have? A wireless mouse with a Dongle, probably the USB port it uses was allowed to power down (see above).

If new, what changes have you made?

On the Control Panel > Power Options, which one are you using? What is the display and sleep setting?

Does the PSU have a clicking problem when PC is sleeping?

Same issue with my new 8960--shuts down randomly (usually when in sleep mode but not always) and must be unplugged from power and re-plugged to power before it will reboot. VERY AGGRAVATING!

@WarBaby​ - If you have an NVidia GPU, did you change the power setting in NVidia Control Panel?

Open NCP and click Manage 3D settings. Then scroll down right pane to Power Management Mode and set it to Prefer Max Performance.  Close NCP, reboot and test waking from sleep. 

BTW: Do you have the latest BIOS update for XPS 8960 installed?  You need this update to deal with Intel's system stability issues when running 13th and 14th Gen CPUs.