I have to same problem.  I have to reboot to wake it up.

Tom

Wouldn't you think somebody from Dell would attempt to answer this question? I'm pretty disgusted with Dell "support".

Same problem here and no help from Dell so far, but I will keep trying.  It must be a BIOS issue as it is before any OS is loaded.  I have tried different keyboards that have "power" and "sleep" buttons as well.

No help from Dell yet. Except their heavily accented "Help" folks, who always want to get into my computer. Last time they took over control, it was a near disaster. I don't think they understand the problem yet. I've tried phone, chat, email. No help at all. Maybe if I wrote Mr. Dell a letter - -

I just finished a chat and remote session where he clicked around for 45 minutes and then told me that my computer does not support ACPI, which of course it does as all computers for the last 7 years do.  I will use the chat log to escalate the problem and see if I can get anywhere.

I have XPS15Z and exactly this problem, the internal keyboard and trackpad will not wake the computer from sleep and there is no "power management" tab in the devices in the device managager. I have got it to wake from an external USB mouse which might help you, the setting for this is in the BIOS, but as you say, pretty poor show that no one from Dell can tell us why the laptop won't wake from sleep using the internal mouse or keyboard ! Shame on them.

As an update, I have it working now but I had to partition the HD and do a clean install of Windows 7.  I would guess it was a driver or a Dell utility that was not working right????  Now it will resume from sleep but not from hibernate or powered down.  This is good enough or me but still not acceptable for a brand new laptop from a respected name brand.

I think the whole area of waking from sleep using either internal or external devices is messed up and what concerns me is that Dell seem to be totally uninterested in looking at it and also if they did look at it and find the answer, how would they communicate that to us as users ? Is there supposed to be an update utitlity for the XPS 15z ?

Just to finish this thread off, from my point of view, Dell opffered me a full refund on this laptop as it appears there is also a motherboard issue with it too. For most people the fact that you can only wake it from sleep using the power button probably isn't an issue, but because I use it mainly with the lid closed (using an external monitor) it was a pain.This is the first time I have come across a laptop that will not wake from sleep using its own keyboard/mouse and hopefully the last.

I bought a 13" MBP instead.

Try these steps to fix the issue

Open the Advanced Power settings for the power plan that you are using and change the Hard disk to Never, USB selective suspending to Disable. Also disable the Hybrid sleep option.

I would suggest also to check disable the Power option for the wireless card from the Device manager as well.

try these steps and let me know

Try these steps to fix the issue

Open the Advanced Power settings for the power plan that you are using and change the Hard disk to Never, USB selective suspending to Disable. Also disable the Hybrid sleep option.

I would suggest also to check disable the Power option for the wireless card from the Device manager as well.

try these steps and let me know

Tried all of those settings, (everything was set to NEVER and DISABLED) so did Dell Tech Support who logged on to it three times - believe me nothing would wake this thing from Sleep apart from the power button or a USB mouse (if you have set USB WAKE in the BIOS. Amazed that natively Win 7 does not allow internal mouse or internal keyboard to wake the laptop from sleep.

Anyway I was given a choice, a new motherboard or a refund, so I went for the refund and a MBP.

Yep exactly the same for me. I am astonished that this sort of basic basic problem is not addressed quickly and effectively by Dell.

Anyway, I am a MBP owner now and happy with that as it wakes from sleep no bother ! :)

I've learned that Win 7 has a lot to answer for. It killed my 2T external hard drive. It hates it if you updates ITunes - I've lost everything on ITunes twice when I update. Since learned Win 7 is the problem. It doesn't play well with lots of things. Thanks again, Bill. Maybe my next computer will be  Mac. Just hate to learn something all over again. But I will.

I went for a refund, too. Got an HP. Simple, real people answer the phone, it works. When it goes south, I'll get another one. A disposable laptop.