How can I format my PC?

Dear Sir:

Would you please let me know how can I format my PC. Please let me know step by step and in detail. I have AMD Athlon, 64 bit 2 GHz. 512 MB RAM with Windows XP SP2 and Office 2003. I have made four partitions C, D, E and F respectively. G is my DVD ROM drive and A is Floppy drive. Would you be kind enough to let me now how to format PC step by step and in detail.

Thanking you.

Rufus