It sounds as though the memory card is the cause of the problem. There are a number of issues with the card that will make the camera display these symptoms. Generally, these card issues can be fixed by emptying the card (transferring photos to the computer) and formatting it using the camera's Format process. The only other is that the card is just too slow (the number in the circle on the label is less than "6").
First, to eliminate any camera software hangups, reset the camera using the attached instructions.
Next, empty the card and format it.
Finally, take some shots and please let me know the result.
Please keep in mind that my diagnosis & solutions provided are directly dependent on the accuracy of your description of the problem. As with any "do it yourself" fixes, success is a "team effort", since I can't see or touch the camera, and relies on the customer's manual dexterity and ability to follow the instructions well. If the "do it yourself" approach doesn't work out for you and you need conventional repair, please let me know.
If you require additional information, please use the Reply to Expert Tab to contact me. Click the ratings only after our exchange is complete and you are satisfied.
If you are satisfied that my answer is accurate or has provided a reasonable alternative solution, please do not forget to rate my answer OK, Good or Excellent.