Micro SD card problem

first of all hello! ;)
I have a problem i tried solving it myself but i really need some help.Its about my Micro SD card of r4 original. I can play on my ds but when i put it in my computer it show problems.
All the time i havent got that problem but now i have.
The computer can't open my SD card and when i try to format it it says error no permission :-\
I tried other USB slots other computer but it says always the same.If someone knows what to do please tell me.

Replying to #1

Do you not have admin rights to your PC?Try someone elses PC, And for R4 orignal try the DSTT v1.17a12 firmware, Or ysmenu to run newer gameshttps://www.romulation.org/forum/index.php?topic=27617.msg466427#msg466427

Are you sure you haven't locked the card (its a little tap on the side of the card you need to slide up)? Just to be sure....