spnetres.dll is a Symantec CMC SpNetRes
belonging to Symantec Client Management Component
from Symantec Corporation
Non-system processes like spnetres.dll 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.