Good Morning!
After letting the reader connected to my notebook the problem is solved!

It now works as if nothing happened.
Paradoxically my computer now recognize the reader as usual.
Though I don't understand the cause of the freezing I am very glad to have my reader "back".
Donnageddon, I tried to reset while the reader was frozen, but the reader didn't respond in any way to sticking the paper clip in the little hole.
Thank you all again for being so friendly and helpful!

I appreciate it a lot!
Lily