I want to upgrade my CPU to the Max my system can handle (im too chicken to overclock it for risk of damage to the system)

I do know that my system is old and that I could get a new one for a decent price. This system is more of a hobby rather than a productivity machine. I have a new laptop that screams past this.

Here is my current setup:

Pentium 4 1.8Ghz  400FSB(Sisosoft Sandra says the type is Willamette-not sure what that means)

I just bought a processor on eBay- it wont fit!

It looks the same size to the naked eye, but its slightly smaller than what I currently have, and I refuse to force ANY sort of component into a socket for fear of damaging it permanently.

I bought a P4 2.4Ghz/512/400/1.525v  SL6GS (labeled on the processor)

I didn't write down what is labeled on the current one, i will open the system again later and get that info.

I hope that I just didn't waste my money (only $33 but hey its money!)

I guess i should have done more looking into my current setup.

Does anyone know or have reference to where I can find the fastest processor my system can handle?