In the Start menu, type cmd, and then click the entry for the cmd program.
At the command prompt, enter diskpart (you might have to approve this operation as an administrator). The prompt line should now display "DISKPART".
Enter list disk.
Enter select disk X, where X is the number of your selected disk.
Enter clean.
Enter create partition primary.
Enter select partition 1.
Enter active.
Enter format fs=fat32.
Enter assign.
Enter exit.