I frequently discover odd quirks concerning file associations. Here's one example.

If I enter
ASSOC.avi
at a Command prompt (a new method I've recently learned about), I get the result
.avi=NeroShowTime.Files

Yet I have AVI files associated with VirtualDub. And, for all AVI files, the Type column in Windows XP Home folders shows 'VirtualDub'.

FWIW, in Folder Options>File Types, I see:
Details for 'AVI' extension
Opens with: VirtualDub
You have customized files with extension 'AVI'. To restore these
files to their default type (VirtualDub), click Restore.

For a long time the Type column *did* oddly show 'NeroShowTime', despite d-clicking opening the AVI in VirtualDub. Can't remember what I did to change that, months ago. But from the above evidence, it's clearly still a bit dodgy behind the scenes. Anyone have any insights please? Some obscure registry ambiguity or redundant entry?

--
Terry, West Sussex, UK

The media player war continues. The various players have gotten better, but obviously, not completely. Realplayer, Quicktime, Nero, Windows Media Player, and others wrestle for control. They used to be real nasty about it.

I have found the easiest way to correct this is to go into Windows Media Player and select Tools > Options > File Types and click on Select All and change them all to WMP. Then, from My Computer > Tools > Folder Options, change specific ones back to other players as needed.

Note that malware can dink with your settings too. You might want to run through your arsenal of anti-malware tools or my sticky, Cleaning Out Malware.