...would I need another cooling fan I have a Dell Dimension 2400. Here are the specs for the processor I want:

Processor Type: Intel Pentium 4
Clock Speed: 2.8 GHz
Compatible Slots: 1 x processor - Socket 478
Cache Level 1 Size: 8 KB

Cache Memory: L2 Advanced Transfer Cache - 512 KB
Bus Speed: 533 MHz
Manufacture Number: RK80532PE072512