Running it on Windows 8.1

Every time I complete a level, the computer reboots. Hopefully, it saves the progress, but it's annoying.

Are you running DX 9 mode or DX 10/11 mode? Since each is technically a separate binary perhaps switching them might help?

I'm running the DX10/11. I'll try the DX9 and let you know.

Did you Run it on Desktop or Laptop ?

if Laptop, how high are you Temperatures ? because Giana sisters wants Power , and so the Heat is going on and on.
if the Heat is too high, the PC shutsdown.

But in this case i don´t think its the Temperatures. did you manage Compatibility Mode ?
if that not helps, test another heavy Program who needs power. like (Uniengine Vally Benchmark)
see what happens there .

Best regards.

It's a desktop. The Witcher also makes weird things, so it could be temperature.

Go for google and search for HWinfo32 / 64 . And start it with Sensor only .

Post your Temperatures here Pls :)

Maybe we can find what is the Problem.

Its also Good if you Post what are you PC Specifications.

CPU / Graphiccard and Motherboard.