weird files keep popping up

every once and a while i get these outlook express files that are around 11 MB sitting in all my shared folders that i share on my network. some times in all my folders and some times in just one computers folders. is this someone leaving crap behind after they crusied my network or is this something to do with winxp?

Doesn't sound normal, I've never experienced that in my shared folders.

Do you have virus software and/or a firewall?

no firewall and no virus stuff thats what i figured it was because its just in my shared folders

What are the file names?

they are copies of files that i already have somewere on my computer but they very