It's dusty in Albuquerque. We have a lot of cleaning to do most weeks. But I hadn't realised we needed to clean inside our computer. Last few weeks, we've been getting some heat shutdowns of the computer. I finally relented, and opened the thing up this morning.
Before:
After cleaning:
That was a whole 3mm of dust over the heat sink, precisely where cold air should be drawn through it. No wonder the thing was overheating. Time to invest in a specialised cleaning kit, I think.