i think my sandisk 8gb micro sd card has a virus on it. it won't play music and when i put it i my phone my touchscreen begins to freeze and phone shuts off. i am really confused as to how i can reslove this problem ; please help !
If you have a virus on it or is otherwise corrupted your best bet would be to wipe it and start from scratch. Use an SD card adapter to be able to insert it in a PC card reader. Then:
-copy the important (and clean )data from it that you might want to use/save at a later time
-Download and install Killdisk
-open killdisk and navigate to the card's root (letter), making sure you select the correct drive (you don't want to wipe something else from your PC)
-use the erase function to erase all data from that card. This will completely wipe the data from the card
-Exit killdisk, then open Disk management (in Control panel>Administrative tools> Computer management) and format the card to your phone's recommended filesystem. Alternatively, you could just insert the card into the phone and let the phone do the formatting.
-copy the files you saved back on the card.
The speed of this(or any) program depends on the state of the SD card and it's health. On one hand, a class 2 rated card will be slower than, say, a class 4 or 6. On the other hand, a card that has been used for a while with repeated read/write cycles will be slower than a similar card that is new. Eventually a card will become read-only, this is the nature of flash-based memory.
In my opinion, if a card is that slow as to become unusable, it's time to replace it and not look back. If you believe the card still has some life in it, you can let it run overnight until the program has finished it's job. The purpose of this whole thing was to remove a stubborn virus from it. Any program you'll use will imply some write cycles on the card, hereby shortening somewhat the life span of the card itself (see above). If the card is somewhere at the middle of it's life span, it will not make any difference, but if it is dying, better to replace it, because this will push the card a little further down it's road.
Killdisk is writing zeroes on the card, rendering it in a clean state. Any other program that does that will do fine. As I have said in a previous post, you could use the formatting utility that comes with the phone (if comes with one). Formatting does NOT erase the card, though, you might end up with the same virus.