how to remove sd write protection

I think there is something I need to do to my computer to get this to work. I
have tried a few sd cards in the card reader. The reader recognizes them, but
won't let me drag and drop photos onto the sd card because it says it's
write-protected, even after I slide the the lever on the card into the
correct position. Does anyone know what's going on and how to fix this
problem? It's driving me crazy. I want to set up digital photo frames, but
can't.

Thanks!

Some card slots are a little snug and the slide lever gets pushed to the
write-protect position (or a little off the write-allow position) as you
insert the card.