accessing files from my xbox through my desktop

I have an XBOX that has been modded so I can store more memory and also tie into my home network. The setup works great but I have a small problem that I need to resolve. I would like to be able to access the memory on my XBOX from my computer so I can delete unwanted files. I downloaded a trial version of smart ftp client from a site but have not been able to figure out how to do this on my own. I have limited knowledge of computers.