Почему Ubuntu 14.04 внезапно иногда замораживается?

Иногда, в то время как перемещение/чтение по Ubuntu PDF/независимо от того, что полностью замораживается. Я не могу управлять ни сенсорной панелью, ни клавиатурой, таким образом, я использую Высокий звук комбинации + Штамп + R + E + я + S + U + B для перезапуска ее.

Какое-либо предложение о том, как зафиксировать это? Thankss

РЕДАКТИРОВАНИЕ 2:

Моим ноутбуком является Asus K53S.

Информация о драйвере:

ale@ale-K53SC:~$ ubuntu-drivers devices
== /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
vendor   : NVIDIA Corporation
model    : GF119M [GeForce GT 520MX]
modalias : pci:v000010DEd00001051sv00001043sd00001762bc03sc00i00
driver   : nvidia-304-updates - distro non-free
driver   : nvidia-331 - distro non-free recommended
driver   : xserver-xorg-video-nouveau - distro free builtin
driver   : nvidia-304 - distro non-free
driver   : nvidia-331-updates - distro non-free

Другая информация: ale@ale-K53SC $:~ lspci-b

00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)

00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)

00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)

00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)

00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)

00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)

00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b5)

00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b5)

00:1c.5 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 6 (rev b5)

00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)

00:1f.0 ISA bridge: Intel Corporation HM65 Express Chipset Family LPC Controller (rev 05)

00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 05)

00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)

01:00.0 VGA compatible controller: NVIDIA Corporation GF119M [GeForce GT 520MX] (rev a1)

03:00.0 Network controller: Intel Corporation Centrino Wireless-N 100

04:00.0 USB controller: ASMedia Technology Inc. ASM1042 SuperSpeed USB Host Controller

05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)'