It was fine until today.Is this a recent development/issue? Did anything change just before this started happening?
Had you previously been working inside the laptop?
NoHad you previously been working inside the laptop?
This is the likely culprit (heat). The old rig may simply be ready to be put to pasture.That laptop had thermal shutdown once or twice.
Besides the fan at 100, everything is normal. But please let me know what does the blue wire do.This is the likely culprit (heat). The old rig may simply be ready to be put to pasture.
https://support.hp.com/us-en/document/c02030599
Could be a sensor issue, a failing CPU, cracked/dried up TIM/pads on the CPU and memory, etc. I wouldn't spend much money to revive this old rig.
Blue wire of the fanBlue wire attached to what? Likely more than one blue wire inside the device. A picture might help as well.