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You'll find those icons in imageres.dll and with you using 64-bit it will be in both C:\Windows\System32 and C:\Windows\SysWOW64
This tutorial will show you how to change folder icons Folder Icon - Change Default Icon
you will need to do basically the same thing for like your Documents, Links, Saved Games etc. all those icons are in the imageres.dll also. HINT: put copies of the imageres.dll on your desktop and modify them to not touch the originals at this time.
After you have modified the .dll you will need to Take Ownership, give yourself Permission, Rename(The original one from imageres.dll to imageres.bak
.dll) and Replace imageres.dll with the one you modified look at Post #6 of this thread and it will show you how to do that Basic Networking Information
After you have done this you will need to Icon Cache - Rebuild
Let me know if you need further advice.