I'm assuming that this is a preinstalled copy of Windows on a laptop. I just posted a similar note about this on another topic. Product Keys from OEM pre-installed versions of Windows are useless for reinstallations. They are only provided for the purpose of tracking OEM licenses. OEM pre-installed Windows are pre-activated and are practically just images of the HDD which is why they wipe everything out whenever you restore to factory defaults. With all of these being said, I do not see the point on why you would want to obtain the Product Key. Unless of course that is an upgraded copy of Windows from a lower edition to Ultimate.
Microsoft has a tool for checking product keys and will indicate whether it is a retail copy or OEM copy. Using an OEM license key will only give you an invalid product key error during installation or activation.
I recommend linux or ubuntu especially. As it's open source it's is very hard for hackers to get into as all the places where they could have got in, have been reported and fixed. Therefore it's safer than windows also it's got very few bugs in it as people will of also reported these and it will of been fixed.