stpmon.dll is a Stpmon
belonging to ST-Print2003 for Windows NT//2000//XP
from SATO Corporation
Non-system processes like stpmon.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.