I added a new hard drive to my old drive. I have only one operating system. My old drive is set for a primary partition. Does this mean my new hard drive should be extended partition only? How would I have to set up my partition for this new added hard drive?

No, it does not.
You are allowed to have up to four primary partitions per one physical hard drive.

Thank you for your answer! :slurp:

I read somewhere that we should have only one primary partition in your pc when you have only one operating system. I think I have one operating system...does this apply to this?

You only need one primary partion for the OS. As Nodsu says you can have upto 4. It does not matter what partion set your new disc to.

You can create an extended partition, and fill this with as many logical drives as you want. Normally, one might have 1 primary partition for the OS and then an extended with several logicals, but if you are only halfing or thirding the disk, then primaries are fine.

Thank you guys!!!!