In customer place, If the TASKMANAGER is Diabled. Please use the following commands to KILL the PROCESS,
1. Open Start - Run - CMD
2. TASKLIST [Note down the PID number for the application which you have to kill]
3. TASKKILL /PID <>
Then it will KILL the Process for the mentioned PID Number
Virus may also disable the Task Manager. Please ask the customers to scan the machine for virus.