|Your hard drive definitely needs to be replaced.|
Laptop / Netbook hard drives never have a warranty longer than 3 years.
You can determine whether it is still under warranty on the Western Digital web site by using it's specific model number or serial number.
If it is under warranty, you probably have to use Western Digital's Data Lifeguard Tools to test it and copy down the error codes or messages it produces in order to qualify for the RMA (Return of Merchandise Authorization), and then ship it to some place they specify at your own cost, abiding by the shipping packaging requirements specified on their web site.
Usually you are shipped the exact same model, or if not a model that is very similar, at their expense, and it will have the remainder of the warranty period, although the replacement drive will usually last at least as long as the original warranty.
Or you could just buy another hard drive locally.
If the laptop did not come with Recovery disks, you have a problem - what are you going to load the replacement hard drive with ?
"Samsung EasyNote "
When I search the web with that, I find only Packard Bell EasyNote laptops.
Samsung may be who makes the Packard Bell EasyNote, but Samsung itself has no such models.