F700BT Reboot Loop Error, Tried Everything Need Help Please!!

[StonedSloth]

Hello, my sister recently bought a car with the F700BT stereo in it, and she was a retard n didnt even check to see if it worked, was stuck in boot menu. Since then i've read about every troubleshooting topic on this website and have tried to update firmware multiple different times but never fixes the problem.. i had done one of the firmware updates 2.006 i believe off the pioneer website and when i would turn it on it would just go to black screen but not continuously reboot, if i hit the menu button the screen would load and have the main menu screen but nothing would work when i click on them will just make the sound n register on the screen that its clicking the button just wont do anything.. then i tried firmware 2.008 n when thats installed it just reboots and main menu screen wont pop up at all when i hit button.. Also tried 3.0 firmware or 3.1FX whichever one it is n nothing..  right now i just have it so that it boots in test mode with the SD card cause i found that if u put in a cd it plays, so my sister can at least listen to music while driving the only shitty thing is that u cant change songs, n when you shut car off it restarts the CD.. I am wondering if possibly the previously owners fucked up system files for something, installing the firmware does that restore the all system files or does that just update the main apps n stuff? If firmware doesnt is there anybody out there that has a complete factory restore file?, I've looked everywhere n cant find one if there is one.. PLEASE if anybody knows something else i can try besides redoing the firmware let me know kinda wondering if its just a malfunctioned unit.. Thanks for any suggestions people have... Peace