how do i use the product key at the bottom of my laptop?

My laptop crashed and I would like to know how do I re-install windows 7 home basic using the product key on the base of my laptop.I have no cd's as windows 7 was already pre-loaded and activated on my laptop when my parents gave it to me (laptop was a birthday gift) Can I just download a windows 7 home basic off the net and activate it by using this key from the sticker? will it work? and also i'm scared i'll lose my microsoft office products once i reinstall my windows. I have a Samsung R530

Many (most) new PC's come with a restore option on the hard drive that will restore the PC to the original factory condition. On Dell's that is F8 at power on. Other manufacturers have different methods. Many PC vendors supply a procedure (usually an icon on the desktop) to create discs that can be used in case of a failure or corruption.

Best to check with the PC Vendor to see what is avaiable or required for your specific PC. You can download a Windows 7 installation file, create an "iso" DVD (bootable DVD) and use that in conjunction with the Windows 7 Product Key. That will install Windows 7 but it won't install all the needed device drivers and you will still need to download those from the PC vendor. MS Office is a separate issue, if you have the product key for that you can download office and use your product key. If not that may be gone, if you got it with the PC from the PC vendor contact them about it.

Can I just download a windows 7 home basic off the net and activate it by using this key from the sticker?

Answer is Yes. But restoring the OS from the recovery partition would be easier. Make sure you first save your own data - e.g. like this: Lucid Puppy way to recover files from a non-bootable computer

It would help those that are trying to help you if they new what kind of laptop you have.