I know you said you checked properties etc...
But...
The only place I know of to do this is My Computer - right click the 'drive' and check that autoplay is set to prompt you each time or set the default option you want.
Alternatively you might want to try a (currently free) but of software at
Picasa which was recently purchased by google.
Once you have installed it there is a picture transfer wizard in it. I don't use it as the Xp one suits what I do.
FSD