I bought the DSTT about 3 weeks ago and it worked fine until today. When I inserted the DSTT into my DS and "No DS Card" was detected. I tried many times and it is still the same. I am surprised that the quality of DSTT is so poor. Did anyone has the similar experience? The store where I bought the DSTT listed that it carry only 7 days warranty only. Probably, I cannot exchange for another one and wasted my money.