Hello

I've got Toshiba m40x-163. From time to time my notebook hangs
displaying blue screen (but not Windows BSOD) with the following text:
Hardware Malfunction, Call your hardware vendor for support, NMI:
Parity Check/Memory Parity Error, The system has halted.

The memory is fine, I've checked it thoroughly with testing programs.
What else may be wrong?

BTW, can anyone tell me should be the indoor range of the built-in
wi-fi network adapter (atheros 5004g)? 

Best regards

Bartosz