One question bluejeans.
When your computer locks up, can you still move the cursor with your mouse? Also if there is sound playing does it continue to play when everything is locked up?
If your mouse cursor is locked up when your machine freezes, I'd be at least 95% certain your problem is heat related.
One thing I've also noticed is that Fan 3 is not spinning and your -5Volt rating seems to be extremely low. Since fans often run at 5 volts, I'd also look into your Power Supply as there might not be anything wrong with the fan, it could just not be getting the power it needs.
If you are comfortable with the internal hardware of your computer, or trust someone enough to fiddle around with your machine's guts, I recommend the following.
1. Unplug your computer.
2. Remove the Side panels of your machine (both of them).
3. Remove your
CPU fan or whatever fan isn't spinning (you may have to plug your machine in and power it on to see which one it is...just remember to unplug it before touching anything inside) Leave the heatsink where it is.
4. Grab a regular household fan that can be set up to blow a great amount of air through the machine.
5. With the fan blowing through the machine, power it on and try running some
cpu intensive applications while running the moitoring software.
If your machine doesn't lock up anymore then we have a heat issue. Now it's just a matter of determining what's causing it.
If this is the case I reccomend trying a new fan. Mainly because I personally would rather waste 12$ then the 45$ or more required for the next steps. If the new fan doesn't spin. I'd replace the power supply. This can be a pretty daunting task if you're not comfy with the insides of a PC so if you're not...please don't risk your entire machine trying to save a few dollars and have it done by someone else.
I don't really think that this is malware related, not to eliminate the possibility and it wouldn't hurt to run through the prework instructions in valis' or my signature, if your computer will allow you as it could end up saving you all the work I've mentioned above and a few dollars.