Crucial technology sd/mmc card reader

I have a Card Reader from Crucial Technology that holds the SD or MMC camera cards that I used to use with my now defunct Canon camera. I used the Card Reader on a desktop computer a few years ago; but am now using a laptop. Having 'rediscovered':-o the Card Reader today I wanted to see what is on the Sandisk cards:confused. One Sandisk card opened and I viewed the pictures fine, so I know the Crucial Tech device is working ok.

Next I tried a Sandisk 256mb card:confused then a Sandisk 512mb PNY (whatever that stands for:confused)then the grand daddy of all a Sandisk 2GB card to no effect? Does this mean that all these cards have noting on them? No, they are all 'unlocked'rolleyes I saw that coming! On some of the above cards they have 'windows can not open this program' of what don't appear to be photo files? One does have 'DSC' file but when clicked is blank:confused

What's up? Thanks