The good new is that the laptop has a modular socket, rather than soldered chip.
The bad news is that you are limited to Pentium 4-M processors, and even then you run the risk of overwhelming the laptops cooling system because it was not designed for any other processor.
Possible choices:
Intel Mobile Pentium 4-M 1.5 GHz (RH80532GC021512) 1.5 GHz 512 KB 26.9 Watt SS
Intel Mobile Pentium 4-M 1.6 GHz (RH80532GC025512) 1.6 GHz 512 KB 30 Watt SS
Intel Mobile Pentium 4-M 1.6 GHz (RH80532LC025512) 1.6 GHz 512 KB SS
Intel Mobile Pentium 4-M 1.7 GHz (RH80532GC029512) 1.7 GHz 512 KB 30 Watt SS
Intel Mobile Pentium 4-M 1.8 GHz (RH80532GC033512) 1.8 GHz 512 KB 30 Watt SS
Intel Mobile Pentium 4-M 1.9 GHz (RH80532GC037512) 1.9 GHz 512 KB 32 Watt SS
Intel Mobile Pentium 4-M 2 GHz (RH80532GC041512) 2 GHz 512 KB 32 Watt SS
Intel Mobile Pentium 4-M 2.2 GHz (RH80532GC049512) 2.2 GHz 512 KB 35 Watt SS
Intel Mobile Pentium 4-M 2.4 GHz (RH80532GC056512) 2.4 GHz 512 KB 35 Watt SS
Intel Mobile Pentium 4-M 2.5 GHz (RH80532GC060512) 2.5 GHz 512 KB 35 Watt SS