Anyone still running Windows 7?

Maybe try downloading HWMonitor—it’ll give you a much better look at what those temperatures are actually doing inside that machine.

Here are the temperature shots:

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The card is an Nvidia GeForce 7600 GS 512 mb

Your card's fan has officially given up the ghost.
Hitting 70 degrees just sitting there at idle is way too high.
The moment you put even a slight load on it, it climbs north of 90... and then—bam—total system freeze or an instant reboot.

Maybe try popping the case open—just to see if the graphics card fan is actually spinning? If it’s sitting still, there's your culprit right there.

I'll look into it, but here’s a quick question from someone who isn't an expert. Is it actually possible to just swap out the fan on a GPU if the card itself still works but the fan is dead? Or am I looking at replacing the entire graphics card?

Replacing it is actually quite straightforward.
Provided you can track one down somewhere.

Then again, maybe a replacement isn't even necessary. Could it just be a buildup of dust clogging things up? Perhaps a simple cleaning would do the trick. Honestly, I’d say there's a fifty-fifty chance that's all it takes.

Both fans are spinning like crazy—the one on the back of the case and the side one right on the circuit board (that's the motherboard and GPU, right?). Is that the fan for the graphics card?

The one in the back is bigger, so it's pushing way more air than that smaller side one. Neither of them makes any noise, though; they're super quiet. I don't know if that actually matters.

I'm losing my mind here. Is it possible the cooler wasn't mounted right, so it's spinning but doing absolutely nothing to cool things down?

We’re talking about the fan on the graphics card itself, not the one attached to the motherboard.
We need to look at the video card—that massive component, likely the largest thing in your rig, plugged straight into the main PCIe slot on the motherboard. Check the fan on that unit.

I’ve got my case open right now, and both fans are spinning like crazy. I already double-checked everything I mentioned in my last post.

What's the move here? Anyone got any ideas?

I honestly have no clue.
All I know for certain is that hitting 70 degrees Celsius while idling isn't normal behavior for a graphics card. Once you put even a minor load on it, those temps spike north of 85, and that's when the whole system either shuts down or just freezes up entirely.

You should probably check if the cooler is actually seated correctly on the card. Maybe a clip snapped, or perhaps the thermal paste has completely dried out—who knows?

Here’s what it looks like inside—both fans are spinning like crazy:

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Neither of those two fans belongs to the graphics card.
Do you see that component plugged directly into the motherboard, sitting perpendicular to the board?
Take a look at the underside of that part—check if there's a fan there and whether it's actually spinning.

Below those two fans—the side case fan and the CPU cooler—there's the graphics card. Looking at these photos, I get the impression it might be passively cooled.

Just to be sure, check the next image where I've circled the area in red. Does the card have a View on imgur fan?

If it doesn't, you might want to just pick up an 80mm fan and mount it directly onto the passive heatsink.

George Sanders37 said:Looking at everything sitting beneath those two fans—the side case fan and the CPU cooler—it looks to me like that graphics card is running purely passive.

Just to be absolutely certain, check the next photo where I've circled the area in red. Is there actually a fan located right here, View on imgur?

If you don't see one, your best bet is to pick up an 80 mm fan and zip-tie it directly to the passive heatsink.

I agree.
Though, just to be safe, he should probably take a look at the underside of the card to see if there's a fan tucked away there.

Heh, just noticed we both posted at the exact same minute 😁

I honestly think he’s dealing with something like this:

so basically, there's no fan at all
it's totally possible the whole thing is just choked with dust...

when was the last time you actually sat down and cleaned out the dust?
maybe your GPU is just—I don't know—straight up dying on you...

Here are some more shots of the inside. You guys tell me—does this card actually have a fan on it? I'm pretty sure I'm only seeing these two:

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The last photo shows the bottom of the case (it’s just flipped over), taken from underneath that white "box" at the base with the red MS Platinum branding on it. Is the GPU in there? It looks like there might be another fan tucked inside, but I'm almost certain it isn't spinning. I put my hand near it and feel absolutely zero airflow.

Here are some more detailed shots:

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It's right under that green paneling used for the balcony area.😁

I checked both the fan and that lower unit, and I'm pretty sure it’s actually spinning.

You’re dealing with passive cooling here.
Check to see if the heatsink—that metal shroud on the card—is actually seated properly.

In that last photo you linked, you can see the graphics card in the top half

Since there isn't a fan on it, I'll just restate my suggestion—maybe grab an 80mm fan with a Molex connector so you can plug it directly into the power supply, or if you have an open header on your motherboard, get the 3-pin version instead

You could probably screw the fan onto the heatsink if there's enough space between the fins, or—in a pinch—just use some plastic zip ties (the kind they use to cuff people during an arrest 😁)