Finally got around to taking the main comp to a local shop and they diagnosed the issue as a failing PSU (thought so). Culprit was lack of airflow as a result of the PSU being located in the bottom of the case and setting the case on the carpet; at least the carpet is clean in the immediate area. I'll order the PSU in a couple of weeks and should be back up and running around mid-May.
Expensive lesson on where not to place yer rig.
