I'm not as familiar with Windows based hardware as I used to be, but those temperatures don't look that unreasonable (hopefully someone else on this forum can give a more definite answer).
However I find it a little unusual that hardware could cause this. My experience with something like a mobo/CPU failure is that it shows up with slow performance, AND very erratic random crashing, freezing, applications quitting with no warning. Does your machine show these other symptoms or does it just run very slow. I've also never heard of a hardware failure causing SVCHOST to chew up all the CPU capacity.
SVCHost from my understanding is a background service that any number of applications can startup or run, so this to me looks more like some sort of software issue (especially if you can reduce load by simply adjusting settings). What I'd suggest as a way to help isolate either to or away from software is:
- boot to the original install disc and maybe run a disc check. If it misbehaves here by running incredibly slowly or crashes then I would lean towards hardware issue
- Clean install Operating system on another drive and see if you can recreate the issue when booted from there. If same issue then hardware, if not then it is more than likely a software issue
My gut feeling is that you were probably getting some weird crashes and shutdowns when your capacitors on your mobo blew, which has caused some corruptions to your hard drive causing these issues.
Anyway, keep us all posted on what you find