The fan sounds like a jet, or it runs very hot while gaming.
Dust packed into the heatsink and a dry fan bearing.
Deep clean and fresh thermal paste. Sold as preventive maintenance — it can be done in batches.
It depends on the model and on what we find inside, so we quote each repair individually. The diagnosis fee depends on the device, and you approve the exact repair price before any repair starts. If it can't be fixed, you only pay the diagnosis.