I have a Toshiba Laptop Satellite L650 with Windows 7 Home Premium, a CPU i5 M480, 4 GB ram and ATI Mobility Radeon HD 5650 graphic cards.
My problem is when I watch a move. Usually 1.7 GB of ram are used but when I watch a move with any player instantly the ram that are used rich 100% with result my laptop crash or perform each task very slowly. This problem starts a few days ago.
So this happens only playing an movie from an external USB HDD. Right?
Possibly this can be related to the USB 2.0 data transfer rate.
Blu-ray movies are very big files because of the high resolution…
This is only a personal assumption but I think that an player which is used for streaming of such big files from external HDD would lock the RAM and this could lead to such notebook behavior…
At the other hand it could be possible that your external HDD is not fully ok.
In such case I would recommend testing this using other HDD.