I am quite new to Object oriented programming. My question is, is the purpose of OOP only to write understandable codes, or does it open new ways and approaches of solving a problem?

Yes.

http://en.wikipedia.org/wiki/Object-oriented_programming

Google & wiki are your best friends, unless of course you live somewhere where you don't have access to these (Like Iran & Nth Korea)

Hope all goes well - don't be afraid to post questions about your code here - plenty of people who can help.

Ok it makes a lot of sense too. Thanks :)