You need to open the command prompt first, then run the command. If you just run it from the Start menu or Run dialog it will just run it in a command prompt that immediately closes. You should get something like this:
Code:
C:\windows\system32>powercfg /list
Existing Power Schemes (* Active)
-----------------------------------
Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e (Balanced)
Power Scheme GUID: 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c (High performance) *
Power Scheme GUID: a1841308-3541-4fab-bc81-f71556f20b4a (Power saver)
I think you showed us all except the ones that matter.

The ones from source Event Log and Kernel should indicate something regarding the startup. You may also find something from source "BugCheck" which is when there is a bluescreen crash. Most of the rest are normal and irrelevant. You may also see useful information in "Informational" type messages, not just errors and warnings. There is one from today shown in one of those images at 12:42 which may be when you had an issue today (don't know your timezone). Also please expand the column for Source before screenshotting, just to make it easier to tell the full source name. Just go through the error events one by one and glance at the descriptions to find ones that say anything about shutting down, hard drive errors, anything like that. (They should show up in the reliability report anyway.)
You can see there are errors for Windows shutting down unexpectedly. Click the "view technical details" option for some of those. Were those times that you think this problem occurred? The reports in reliability monitor should be realtime, as it's generated every time you open the app.
Edit: I just saw one of those details, hadn't looked at all the images. It shows a network adapter dump file but I'm not sure if that's normal on every crash or an indication that the network driver was part of the cause.
Aside from the System events that you've shown, you an also glance at the Application events. There shouldn't be an application causing this, BUT, Windows could possibly be waking itself up from sleep to run some task and then crashing, rather than actually being asleep when it happens.
Look for events that happened at the same time as one of the shutdown events in reliability monitor.
Have you tried disabling sleep completely and letting it just sit for a long time (usually still letting the screens sleep would be okay). What's your pattern of usage, do you let it sleep very quickly even if you're coming back within the hour, or does it only sleep after like 4 hours? Are you only finding that it has crashed if you haven't touched it for a whole night or does it sometimes happen even if it's only been asleep for 20 minutes?