your system is trying to guess what you want to run and is loading in to memory before you need it.
ie prefetch / cache.
after 5 mins or so of idle the system process will start to use memory to do various system functions. for example it will do background
data checks on sections of your hard drives and make repairs, locate and fix (mark bad, bad clusters, weak spots,...) it will also sync files to cloud servers, do background copies, lots of stuff. Main thing is they should stop/reduce soon after you start to use your machine again.
as to the prefetching there are tools to see what is being loaded in memory for you. I looked at mine and I have plenty of ram and there was a game that I have not used for months being preloaded. (just in case i wanted to run it) this is pretty normal. If you want I can tell you where to get the tool. it is on the microsoft website under internals i think it was called rammap64.exe. you can also use the tool to clear the various data sets it used to preload data
it looks like you have a user mode program that is using up all of your virtual memory. That is
you have 38.2GB out of 38.7 GB max virtual memory in use (max pagefile space on your hard drive)
you have to kill the program that is using the memory in order to free memory to run another program.
(or expand your page file to a larger size if you still have hard drive space, (bad solution))
best to find the name of the program, then kill it or reboot and run the rammap64.exe to watch it as it grows in memory consumption to figure out what the program is.
computer dosent have enough memory to open the program
run msconfig.exe select boot tab, select advanced options and confirm that there is not a checkbox checked for the maximum memory in the boot advanced options. (it could be set to 3gb on a 10 gb RAM system, a person might do for various reasons)
It's probably something like a Microsoft Search function. Task Manager doesn't report everything, though I think anything hidden would have to be part of Windows 8.
In my case I think I had to disable Microsoft Search, but find the program causing the issue then Google the name of it, mention high memory usage and find a solution.
Your above solution can't be correct as he's using 9GB of memory. Look at the picture he includes. There's no cap set anywhere. If the system had a memory cap, then it simply wouldn't use any more for anything.
BTW, you are creating a bottleneck by running three sticks of RAM. That forces the system to run Single-Channel mode instead of Dual. Look at your motherboard manual, then use the configuration for TWO sticks only. I'm guessing you have 4+4+2, so just use 8GB (2x4GB) instead. It depends on your CPU and game/program you are using but you might be losing between 10 and 40% of your performance.
I have 8GB currently installed, and when I turn on my Windows 8.1 PC it uses about 2.4GB. It sometimes jumps up to 6GB or so if I game but usually drops back down below 4GB after the game. While Windows does cache things, the memory manager should never use as much as it has in your case. Again, mine was a memory leak with the Windows Search program or similar function. As I write this I'm at 2.4GB/7.9GB looking at the same graph where you show 9.0/9.7GB but I was over 90% before I discovered the problem which RAMMAP helped fix. I had 16GB when my large memory usage happened (waiting replacement memory so have 8GB now) and the Windows program was using over 10GB of that.
Windows 8.1 has some memory manager fixes as well.
edit, ok now I see the 9.0/9.7 gb (93%) at the top of the page.
I figured the memory limit could have been set, the in use + available was about 3 GB on a 10 GB system
sometimes people do that and put in alternate diskcache or ramdisk software.
The main thing was all the virutal memory in the machine was tied up 39gb on the drive
if it was the search index you should be able to
start cmd.exe as a admin
net stop "windows search"
and I think the system would clean up the memory allocations
then you would want to go and delete the now very large search index at