It happened to me a while back when I tried to run Dirt 3 from steam the cpu and memory usage shot up to 100% and locked up the computer so I uninstalled dirt 3 and reinstalled and it was fine. Then it happened again with Skyrim but it wasn't through steam and I gave up on it. Then I bought the deal off humblebundle.com that came with saints row the third through steam and when I try to run it the cpu and memory usage jumps up to 100% again. I use the SSD for the os and other programs and the HDD for games and media. I searched for a while about this problem but nothing solid on it was hoping someone here may have some experience with this. This computer is not even a year old and this is driving me crazy. I have re-installed windows since the first time it gave me this problem also if that makes a difference. Any help would be appreciated.
Just as a check, Ctrl, Alt, Del, key all together.
Start the task manager, and have a look for these in the processes tab of windows task manager.
Stdrd.exe or Mediacentre.exe.
If you find these take a note of how much cpu time they are taking up. It is Malware and very sneeky and takes up alot of the Cpu cycle time. To remove it use Malware antibytes.