Why would you want to do that ? There are many apps that have their own custom bootmanager included, but they all do about the same thing as the standard win7 bootloader...
All boot managers work the same, anyways to unistall your current boot manager simply use a loader. I don't recommend this but its the only one. Use the 7Loader eXtreme and go to Advanced -> Then click Uninstall BootLoader Files.