No, it's not a Transcend card (with which I have actually had good experience in he past). It's a PNY card (whatever that is). I'm pretty sure it's a cheap, drugstore brand card. The d3100 is my wife's cam she got a couple years ago with two of these cards, both 8gb each. I've always known that I should replace them, but we don't use her camera enough to think about doing it (I use a D300, mostly, and so new SD cards aren't usually on my radar).
Thankfully, the pictures aren't of a once in a lifetime experience. They are memorable, for sure, but not critical. I'll hang onto the card to see if I can ever manage to find a way to recover the shots economically, but I'm definitely going to buy a couple of new SanDisk SD cards very soon.