How to download music from iTunes to my iPhone4s?

Okay so before I was able to highlight the song and drag it to my iPhone file thing. My laptop had issues recently where it had to be cleared out and rebooted so all the programs, files, pictures, documents were erased on my laptop. Afterwards I re-installed iTunes and downloaded two new songs and it won't sync onto my iPhone file! It just kicks it out when I drag it onto the iPhone file. Help me what should I do? I heard it was program to sync music on one computer but it's the same computer!

The iPhone does not allow you to drag music into it. Sorry, try right clicking on the device name in iTunes and clicking 'transfer purchases'. Best answer please, good luck: D

Ok so that doesn't work. Just log into the account you used via your iPhone and download it from there it should be under "purchased". And next time to avoid it download music from iTunes via your iPhone.