Win8 dwm.exe @ 100% cpu while idle?

I have an Asus k5t3a laptop. Started with win7 and upgraded to win 8 awhile ago. When I leave the computer for 10 minutes the fans go to high speed and will stay that way until I come back. If I click resource monitor quick enough I see that dwm.exe eats up to 100% of the cpu. I've tried searching google and have found some threads about this problem but haven't found a true solution.
Being as I'm limited in my computer skills can anyone mentor me thru this? Being self taught, in some areas I have knowledge but there is some areas I don't even know what I don't know....
Right this second I'm heading to work for several hours so I won't be responding right away.

dwm.exe is the Destkop Windows Manager. It's been known to sometimes use all the resources at idle if Outlook is running or if you use a 3rd party antivirus such as Avast or AVG.
My only suggestion at this point would be to shut down Outlook or disable your antivirus and see if that solves it.

@CaptainChaos Thanks for the answer. I've been running windows defender for quite awhile but switched to Avast about a month ago. The problem was there before I switched. I took your advise and shut off Avast and no change, the dwm.exe was hogging cpu. I then tried suspending explorer.exe and again no change. Until I restarted explorer I couldn't switch between program windows, so at least I learned one of the things that explorer does.
I did know that dwm was a windows manager, and it seems weird that it hogs resources when the screen is black, and should be sleeping. I have the on/off key set to "sleep" and if I put the computer to sleep that way, then it usually stays good. But occasionally it will awaken on its own and dwm.exe is hogging cpu again. I suspect it may be some program that is allowed to update or run at certain intervals causing this behaviour, but haven't been able to narrow it down.

Is it possible to have a recording of resource monitor happening in real time so that I can see the last 1/2 hour or 3 to be able to see what's happening while I'm gone?

Bot net :) Better go looking for some malware. At least open task manager and take a look at what is running closely.

I had that thought. I've used malwarebytes and a couple others and they have come up with nothing. That said, I'm a little lost with this stuff and may be doing it wrong. A step by step for a newb would be helpful.

I have task manager running and will see if I can catch something.

You running the new version of Malwarebytes ? It has issues. I like to pair malwarebytes with