Ok,another question about a memory card?

When I connect my usb cable to the comp,the phone will charge,but i want to send ringtones and stuff to my phone, if i get the microsd card,will the comp recognize it and i can store stuff on it? ive tried windows mobile 6.1, but it worked for like a week...and it hasnt been right since....but will the memory card be ok to use if my usb cable works ?this is for the samsung blackjack 2