There can be many causes for this. Hardware 2 most common causes. Ram Pull the ram out clean the contacts with denatured Alcohol and reinstall Power supply dieing or undersized Remove the accessory from your computer see it that helps otherwise replace. Software any number of viruses or spy ware could cause this. possible solutions. run antiviras or antispyware programs
Your camera does not support SDHC cards Any SD card over 2GB is a High capacity card. Use any SD card 2GB and under and it should work without a problem.