To stop it from running, you can probably edit the registry under the ‘run’ and ‘runonce’ keys. If you don’t know what those are, just search on the web and you will find their exact location.
Otherwise, find the executable name (b4playing.exe?) and do a search in the registry… when it is under a ‘run’ or ‘runonce’ key, then delete.
NOTE: Do not blame me, though, if you know nothing about registries and screw up your pc 