Screensavers are a type of video file (sort of) which plays fullscreen after a period of inactivity. A desktop background cannot contain videos, it must be a picture. So you cannot make your screensaver your background, but you can try and find a corresponding picture on the internet.
Find it online?
There is an online screensaver provider known as Cozy that may be able to assist you in your search for a screensaver featuring a birthday party. This would be a good start.
You go into settings: you'll find it out from there.
The Google Screensaver program is included in the image-editing software Picasa. To setup Google Screensaver a person first needs to open Picasa. In Picasa, click the "Tools" menu. Next click "Configure Screensaver". On the "Screensaver" tab click the "Settings" button to configure display options and photo sources. To activate the Google Photos screensaver a person need to select checkboxes for the photo sources that the person wants to be displayed. Click the "Configure" button to get more information on each source. When finished click "OK" to save any changes.
Download limewire, a file sharing program.
Might only work when the computer is asleep. There's a background; the wallpaper when your computer is active/when you're doing something on it, and ten there's the screensaver; which is the wallpaper when the computer is asleep. Make sure you have your slideshow set to the one you want. Then there may be a timer for how long after inactivity begins before your slideshow starts. You should be able to find all of this information if you right click on your wallpaper and hit personalize. By the way, most computers don't allow a slideshow as your background, but only as a screensaver.
Adobe Acrobat Reader is a very large program (some would even say bloated). It runs many services in the background for DRM enforcement and update checks. You may find it prudent to use a smaller program, such as SumatraPDF or Foxit.
With the operating system on your laptop comes a help function. You find it in the configuration, start - configuration. Of course if you want to use a personal picture you would have to load it first on to your laptop.
There are so many web addresses that offer free screen savers that it would take forever to list them all. Screensaver would probably have as many as anybody. Free ones can be found at download's website.
Ok, firstly make sure that your desktop is showing. Right-click on the desktop with your mouse,select the option: Personalize, find the option that says: "Screensaver" and then configure it to something you want.
Just go to Google and find a picture you like. Then save it to Downloads or to a folder. Once it's there, just right-click on the picture and click on "Set as Background". Go to your desktop and it should be there.
Reddit, 4Chan, or even google (possibly)