Hello Kramer, and welcome to Seven Forums.
Your desktop icons would normally be automatically arranged when say explorer is restarted, screen resolution is changed, games (because screen resolution may change), etc.....
If you like, you might give the free programs DeskSave
a try to see if they may help, and which one may work best for you. They save your desktop icons and positions, and lets you quickly restore them if they get changed.
Hope this helps,