Mime problem

["Rob Brown-Bayliss" <uncertain.genius@xxxxxxxxx>]

HI,

some how nautilus has loast all reference to file types and
applications to open them with etc etc,  every file is presented with
a generic icon, and I have to choose which application to open it
with,

How can I reset all the mime data other than editing the properties
for every file type by hand?

--
Rob