A year of service can easy be all you got from that memory card, hell i had high end cards which lifetime in the first go i had to measure in hours and not days, warranty replacement working fine.
I also have memory cards in daily use so old i cant even remember when they first saw service, it can be a crap shoot some times, and thats why its important to buy your memory from a reputable source.
AS CYA say if you dont have another memory card to try with then at least run a test of the current memory card, H2testw will call out a bad memory card, though i have also experienced a single time where a card passed the test but just would not work in that camera ( so i put it in another one which was fine )
I did the test using the Lexar card that I purchase with the camera in September and here are the results.
Warning: Only 165 of 61140 MByte tested.
Test finished without errors.
Reading speed: 71.7 MByte/s
H2testw v1.4
Looks to still be good, I have not been able to use the transcend card due to the memory error