semwltray.exe is a wltray.exe
belonging to Sony Ericsson 802.11 Wireless Network Tray Applet
from Sony Ericsson Mobile Communications AB
Non-system processes like semwltray.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.