If its coming up on start up the most likely way to stop it is ,
Run Msconfig
From Msconfig , you can Change what programs Start on your computer. you might see it in one of the Lists
The Start up list in MSconfig includes the Start up folder and the Run Key in the Registry.
Startup => You can find this in the All Programs Menu. if its there just remove the short Cut, and it should stop Running, also if there is a short cut there , if you check it properties it will lead you to the File location
The Run Key in the Registry.
HKLM>Software>Microsoft>Windows>Current Version>Run
Look for the file path to the Program , if you don't know which one it might be Edit the key and add a ' to the start of the string, that will stop it from working ,and will be easy to undo if its the wrong one
It may be running as a service in Interactive mode, so check your Services, to see if its there.