My laptop becomes weirdly unresponsive in regards to audio and video after about 10 min or so of being on. Any youtube video takes ages to load and when it does there is no audio whatsoever. Netflix videos don't work and windows notifications even freeze. My laptop model is the Aspire E5-575G.
My sister had that problem with her laptop and it turned out that its heatsink was densely packed with dust, pegging the CPU at over 90C and causing constant throttling after a few minutes of use.
This laptop is relatively new (got it in August). I can still do things like open programs and stuff just audio/visual stuff basically stops working. I don't think that much dust has collected since I haven't been using it a lot and it has not been in places where there is a lot of dust/hair to go in through the fan.