Keith, a fresh install will rule out any possibility of hardware.
Its the easiest debugging, and you said, the system was fine for what you needed, so im guessing more on a software issue then hardware.
If your still running into problems after a fresh install, then u can start debugging hardware.
But until you ruled out its not software, u cant start guessing at hardware unless u see physical damage on said hardware.
If ur hesitant to reinstall windows on your main drive, get a spare drive and install it on that, just so you can see if u can rule out hardware.
And if ur still running into problems, then you can debug the hardware, and swap out parts, and reinstall the old drive.