I've been using the following SD card:
PNY - 8GB High Performance Secure Digital High Capacity (SDHC) Class 10 Memory Card
All of a sudden, my Pi will not boot. So I throw in another card and the Pi boots up. So the card is corrupt. I reformat it, and try again. Nothing. So now I want to know if the card is really bad, I reformat it and try storing some files and retrieving them from a PC. I am able to store data on the card.
My question is, if I can store and retrieve data why cant the Pi boot?