I have recently changed my card to a Lexar Pro class 10, 600x speed. As I though this might rectify the problem, but it is still happening.
It seems to happen mostly when I am using the flash. Please help.
You did the first logical step by getting a brand new card. Now the second step is to set the camera back to factory defaults.
See your manual for info.
Remove all batteries for 20 to 30 minutes. You can recharge the cameras battery while you are waiting. You should have to reset the date and time.
Giver her a try!