3duserpic.exe is a 3DUserPic
belonging to 3D UserPic for Vista
from Andreas Verhoeven
Non-system processes like 3duserpic.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues.