The very first thing I found on internet was "The Code 43 error is one of several Device Manager error codes. It's generated when Device Manager stops a hardware device because the hardware reported to Windows that it's having some kind of unspecified problem."
The solution seems to be to replace the card. Since you said you did everything you could do, I have to conclude that you can't do that yourself, so you have to find a repair shop to do that for you.
My problem start few days agos when I was playing peacefully when suddenly my computer froze and was making rainbow square. I restart it and it was making like green square, little but I can still see my screen, and when i'm playing i'm at like 1fps (i even lag on paint). I check on Devices manager that my graphics card (NVIDIA Gefore GTX 760) has code 43. I try everything I found on internet, reset the computer(but I kept my files), reinstall the driver, I did everything I could do, and now I don't know what to do anymore, can someone please help me?

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