partition

i have 500gb seagate hardisk, i just instal os in c drive ie 30gb and remaining are unparttioned space.when i goto diskmanagement tools and clicked unpartitioned space to create 2 partition, but there shows 2 types of partiton ie primary and extended and logica is not showing.can u help me any one pls

Download the Easeus Partition Master Home Edition - Free software downloads and software reviews - CNET Download.com to create or resize your partitions. It's very easy to use.

I am not expert in computer. I want to know when we buy new computer want to install new window. How the partition is complete. I don't idea about partition of hard disk.

Usually the /sales engineer will do the partition , of the Hard disk, or if OEM loaded OS computer , it MAY have at least three partitions.
usually C D & E
C: keep your OS application programs
D: your music files /video etc
E: Important data files/records / bank statements etc. and may be, crash recovery data.
Easy to make back up copies..

Para two : OS when you buy from same dealer , he will load it for you . And ask for the partitions. to be done.
Only chance to get max technical help from the dealer !!!

can you post the screen shot of your disk management screen ?