I have the same problem.
By changing the RAM for another one that I know works well, I have managed to get the PC to always start up correctly, but error C1 continues to appear when it starts up.
However, the PC is running terribly and is newly formatted, everything is very slow.
Does anyone know if there is a solution to the problem? Now that my PC starts up, could I do something in the BIOS to try to fix it?
Thanks