IF you've been running it since we first talked, and nothing has happened, and no further smells or smoke have happened, AND the voltages are fine in the BIOS (Which is where they are the most likely to be accurate, beyond what is reported by any windows utility), and you haven't noticed any unusual behavior, then it's probably fine and you may have caught it in time. It's likely what you smelled was either the carpet that got hot and burned off some of the crap that always gets accumulated on carpets over years of use
(You don't even want me to go into what's found on the average carpet fiber when inspected in a lab. Suffice to say, no matter how clean you think your carpet is, there's stuff there. If you've ever smelled an electric heater firing up for the first time that season after not being used during the warm months, then you know what I mean. And the heating elements don't get walked on, drinks spilled on, food particles clinging to them, etc., like a carpet does.)
or the nylon or polypropolyne fibers of the carpets themselves. If you've ever burnt nylon rope, again, you've smelled it. I guess the main question would be whether or not what you smelled resembled the smell generally associated with burning electrical or seemed to fit in better with the idea of the carpet having gotten hot. I've seen many locations where computers have sat for some time, that are entirely discolored simply from the prolonged exposure to the close proximity of the power supply giving off heat, and that's without actually being in contact like yours was or blocking the airflow, which was almost certain.
I really think testing is the best plan, but if it hasn't damaged anything yet, it's probable that it was caught before it became a bigger issue. I think I'd still start planning to replace it with a good unit though. Anytime you overheat a component, you've shortened it's lifespan and weakened the unit.