What are the Win98 Startup Group Files?

When using the System Configuration Utility, there are a number of “undefined” files running in the Startup Group. Viewing their properties sheets doesn’t give a clue of what “won’t happen” if they’re deleted — some don’t even have an owner.

How can you tell if it’s safe to uncheck a given file? Is there a way to find out what a file does or how it got into the Startup Group?