Processer overheats and trips off on hi tem

Just watching youtube causes the temp to reach 240 and shut down the computer,,, cans at 6000 rpm gives some extra time.

fans are clean.

Model Name: MacBook Pro

Model Identifier: MacBookPro1,1

Processor Name: Intel Core Duo

Processor Speed: 2 GHz

Number Of Processors: 1

Total Number Of Cores: 2

L2 Cache: 2 MB

Memory: 1 GB

Bus Speed: 667 MHz

Boot ROM Version: MBP11.0055.B08

SMC Version (system): 1.2f10

Serial Number (system): W8609DDRVJ1

Hardware UUID: 00000000-0000-1000-8000-0016CB8AD56F

Sudden Motion Sensor:

State: Enabled