Help, needed with my sandisk 8gb got write protected autmatically :(

I am having a san disk 8gb pendrive, i m using it on my dell inspiron laptop, windows 7 basic home edition, it was working fine, but now it has got write protecetd automatically, i cannot delete anything from it neither format it, i tried it on other computers too but it didnt worked, it tried solutions for registry editor available on net bu that didnt worked too…what should i do now :(…help needed plzz