This is the session manager subsystem, which is responsible for
starting the user session. This process is initiated by the system
thread and is responsible for various activities, including launching
the Winlogon and Win32 (Csrss.exe) processes and setting system
variables. After it has launched these processes, it waits for either
Winlogon or Csrss to end. If this happens "normally," the system shuts
down; if it happens unexpectedly, Smss.exe causes the system to stop
You can't end the task. It's a necessary windows process that is needed for the operating system to run properly. If you post what the exact message is in the pop up, maybe we might be able to help you better. As has been suggested, your best bet is to download spybot, ad-aware and an antivirus program and scan the computer. Also, try right-clicking on all those little icons in your task bar and ending those unecessary processes as it's more than likely that one of them is causing a conflict.