Huh.

Last time I was on a XP PC, I remember some files having deleted extensions (filename was something like: "file" instead of: "file.ext")
Thing is that XP still "knew" what the file was, meaning that the OS kept a record which told it that this or that file has no apparent extension, but it's format is ".ext"
Get my point?
OS X does that (I always delete the extensions of my files since I always rename them) but if you save a file without extension, then it won't know what it is. For example, if you download something via a BitTorrent client and when asked how you want to save the file, if you rename it from "file.avi" to just "file", OS X won't know what is is.

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iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

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