Unless you have a very sepecific reason
why you'd want to remove 'old' DLLs, I think you'd be much better off leaving them in place rather than try to delete them - unless you're very comfortable
with what you're doing.
If it's stuff that accumulates from old programs after you've removed them you're worried about (due to half-assed uninstallers that didn't clean up properly), you can get rid of much of it going forward
by using a more thorough removal utility like Revo Uninstaller
. There's also a Pro
version of it available if you need the extra features it offers. For me, the free edition works just fine. More info and download links
FWIW, orphaned DLLs shouldn't become active once a program is uninstalled. So this is one of those situations where the old adage: If it ain't broke - don't fix it!
is especially relevant. Because you're much more likely to screw things up by inadvertently removing something you need than you are to experience a performance or security problem leaving it alone.
Just my 2¢ anyway!