CLI.exe is just there to run an 'Easy Access' task bar icon for the ATI diagnostics function, usually included in the main programs too.
You can stop it from starting by pressing START..RUN and enter MSCONFIG, goto the START-UP tab and locate the offending .exe then uncheck the item.
You will find the icon does not appear and it will cause no ill effects other than having to open the 'All Progams' menu if you really need to run it at anytime.
Note: Apart from your Antivirus and Firewall which you should not prevent from starting at boot, most if not all of the items listed in the start-up menu can be unchecked without causing a problem, so reducing boot times and running processes, Suggest you make a list of whats there, do a little research on each item and uncheck those you do not normally need.
Most of the items listed you will find you do not normally require to be running all the time, Sound and Video Consoles ect as once you have set them up it's not often you need to make changes, a little time taken on this can free up a lot of resources other programmes.