Download HWMonitor from CPUID check what temps or voltages go high when it shuts down, you can log the readings to a file and post it here if you can't make it out.
If you don't want to do that you can try disabling "Current Video Quality Settings to Internet Video" from the CCC in Video Settings.
And check if the problem reoccurs.
Which ones are "they" please specify both GPU and CPU temps.
And Temps are preferred in C.
Mine run at CPU:127F/52C and GPU:125F/51-52C
I don't see a problem there
I looked at an error log for my computer and it shown that my video card was over heating at several different intervals, running a youtube video as well as Team Fortress 2, which caused my computer to shut down. I'm also hearing a sort of 'knocking' noise within my tower when I'm using my computer. I have a suspicion that it might be the fan isn't inserted correctly?
If you're using HWMonitor Pro then under the Tools or Options they have that box to log to a file.
In the standard version you can only save the monitoring data through the File Tab.
For changing the Video quality.
Open the CCC ( Catalyst Control Center)
In the left panel go down to Video Settings
Now scroll down the Right Panel, you'll see one entry with Optimizing Internet Video. Make sure it's off.
Disconnect all fans in the case and see if the "Knocking" is still on, I'm saying this because this is the first case of Knocking I have ever seen, Fans usually run pretty fast 600 to 1200 or 1800 RPM, they usually can't knock at those speeds, you can hear them screeching , brushing, crackling, breaking but not knocking.
You may have a wire with a socket dangling in the case that hits a fan blade every now and then and recoils into some part of the rig that could be "Knocking" or then the HDD knocks.. and that's not very good.