>Hi,
>
>I have a Flash USB drive. I could plug it into a computer (tried on 2 computers), first it worked and I could copy files to this flash drive. But then it stopped working; showed no information. Even though when I was plugging it into the computer, a letter drive was assigned and I could see it in the Windows Explorer. I tried to format but formatting would fail.
>So I decided to destroy all information on this USB. I put it in the microwave for about 5 seconds, 3-4 times (I didn't want it to melt). Now when I plug this flash drive into a computer USB, it won't even show in the Windows Explorer. Was I successful? :)

Would not bet large sums against motivated adversary...
Strip the casing to see chips, identify memory (size should do it),with that: increase surface (pulverize best, drilling holes plus hammering ok, melt/burn remains