by using a program to delete the entries or manually doing it your self..said entries are usually in your registry, and by using regedit one can go in and delete them...

I just had to do this yesterday whilst dealing with the pipas.a trojan...no program would delete it, though Spybot would detect and delete ONE of the entries, but not totally kill the sucker..so in the end I had to boot into safe mode and delete the .exe that was being slealthy and changing its name every boot up, and then delete the registry entry..seems to be gone now...