The green thing is exactly what everyone has been saying it is, ducting from the fan to the processor. The 2 copper tubes are heat pipes that use convection to wick away heat.
Take off the heat sink, clean it with alchohol, and re-apply a good thermal paste (artic silver). Dell uses thermal pads, not pastes, its bullshit that breaks down over time, and 5 years is a lot of time.
This is now 3 people giving you exactly the same advice, why dont you try it before posting again.