The two most common problem areas are the power supply and the SD card. Check your card with the "h2testw" freeware, format it in your PC to FAT32 protocol, then do an in-cam format. If you still have problems, suspect the PS or it's cabling. Note that Windows-supplied formatting tools will not format any card over 32GB to FAT32, but freeware is available for that in SDFormatter, MiniAide, and may other similar programs. Also note that the USB ports on your PC and in your car probably will not power your cam correctly. Almost all the at-home cellphone chargers will, so try the cam that way if the card seems OK. If it's good there, then the problem is in the PS or cabling you're using in your car. If none of this helps, try a hard reset of the cam- check the manual for where the reset button is- usually a paper-clip sized hole in the case somewhere. Carefully push in with a paper clip till you feel a click or feel it stop, hold a second, then release. If this still doesn't do it contact your seller for additional advice or for a warranty service.
Phil