I'm new to Limewire and would like to know what it means when the box pops up and say "We've detected a corrupt file". Is that a file with a virus in it or what?

Possibly, but I think more often it means something is not right within the file. Missing information etc. I usually discontinue the download or delete the file. If you search the forums here I believe you may be able to find links to some programs that may be able to repair these files

THANK YOU VERY MUCH...Just wondering because there is this one song that every single time I try and download it, every user I download it from the file is ALWAYS corrupt from all the different people.

It is possible that it is the same file being shared. For example it was originally dowloaded and then that person decided to share it. So the same original file keeps being shared.