Gfx issue sounds like a sync problem, so could just be settings or a crappy connection somewhere.
59 degrees is not that bad, hdmi cables can be a pain, but spares can be picked up relatively cheaply. As you say unplug everything including the card and do a good clean.
I recently cleaned my computer out, dust everywhere after I used the compressor on it
I found it was worthwhile buying a disk recovery program, some time ago, but have a look around. You can get some which have a thirty day trial period, which are good enough for recovering your saved files, and may even recover the complete local game content.