Conditions:
1. I have an old laptop. Its CD drive is not working and doesn't have floppy disk drive.
2. It had a problem with its original hard drive, so i replaced it with another hard-drive(formatted).
Query:   Now how can i install Operating System on it?
I've got Microsoft XP and Ubuntu available but I would prefer Ubuntu. I'm looking for genius who can enlighten me and instruct how to install OS on it??
Thanks in advance...

damn thts a big problem!!!lol!!!!!..............jus go to best buy n talk to the geek squad bro!

use usb installarion

Install Ubuntu from USB:
https://help.ubuntu.com/community/Installation/FromUSBStick

Install Visata from USB:
http://www.techmixer.com/install-windows-vista-from-bootable-usb-flash-memory-drive/

It may be worth it to try. 

Your CD does not work and you do not have floppy drive seems you are locked out. Lets do it primitive (gaule) way.

How about you take your hard drive out and put it in another laptop, or  you can get an adaptor (get one from best boy once done return it), laptop to desktop and install the  software. Once your put it back , your laptop may able to recognize pre-loaded operating system. 

You may get cd player for 2-5  bucks? Go CRAIGSLIST.ORG/  YOURCITY