I’ve got this uncanny Samsung Netbook, it has Windows 7 creatively commissioned as well as as I’m not used to this operation system, we can’t appear to be means to shift a desktop credentials – as well as it’s so very, really irritatingly blue. So any assistance would do. Thanks already.

It most likely has Windows 7 starter which is a stripped down version of Windows 7. This feature is disabled. You might do a search for some 3rd party software that will let you change it tho.
It’s because you’re using Windows 7 Starter, which doesn’t have any personalization features. To change the background, you would need to upgrade the OS.