if you are running winblows either bash the machine with a big hammer or install linux, if its a linux keylogger:
1. open a console such as xterm
2. type ps aux and hit the enter key with a brick, ok dont hit it with a brick

3. check the process list and find the pid of your keylogger and if the location of they keylogger is in the command write it down
4. kill the logger with kill pid
5. run ps aux again
6. if the logger is still there type kill -9 pid
7. check the boot services for the keylogger, if it is not there check the cron jobs of the user who was running it incase the command was triggered at boot by a user cron job, once u find it remove it from booting
8. reboot
9. open a console again and run ps aux, if the keylogger is there kill it again, remove the boot job again and delete the keylogger app, then do a search for anything with whatever the keylogger was called in the filename, delete anything u find if u think its keylogger, beware there are many system files with names such as key.
10. if that dont work try an anti-spyware or an anti-virus