Although this is a computer problem, it does relate to your Acekard so fair enough
Now try a different way of plugging it into your computer. Try a MicroSD to SD Adapter and plug it into your printer or even try the MicroSD USB that came with your Acekard.
I had this problem but lucky for me, I had DSFTP on it and I set up an FTP server with my DS & Computer so I was able to snag all my saves before reformatting again.
You could also try a different OS like Ubuntu to explore your SD and snag your valuable data. If you wish to do this you do not have to install Ubuntu simply select to try the OS without installing after you boot it.
If you wish to just format and attempt to snag your data afterwards, I suggest using Recuva and using a Deep Scan. It won't guarantee you'll get your data back but you can try & take the chance.