Windows 7 - ATI Display driver stopped responding and has recovered

spec:

window 7 32
CPUID CPU Name Intel(R) Core(TM) i3 CPU 540 @ 3.07GHz
Asus p7h55
Radeon hd 5550
ram 2gb
Power Supply 500w

i keep get Display driver stopped responding and has recovered .

what the problem was? please help me, thank you.

Please update your Radeon drivers
AMD Graphics Drivers & Software

This is a TDR error generally caused by corrupt drivers or defects in your GPU/RAM
Test your RAM RAM - Test with Memtest86+

this is a fresh copy of window, but it's not up do date.

it's a latest ati driver.

what is GPU ?

i have 2 git ram.

sorry, im not good at computer.

sorry i want to ask one more question...is it not enough ram? could it possible?

GPU stands for Graphics Processing Unit in simple words Graphics Card/3D Card/VGA (Radeon HD 5550 you have) no its not about RAM is less or not. Test your RAM's as yowanvista has mentioned.

i see...does it related to not enough ram? cause the gpu is NEW !

No its not related to lack of RAM, be aware that even new components may have defects

Do the test above and report back

Recently i had purchased new pc With Follow details:
Processor: Intel I7 2600K
Ram: 4GB DDR3x2
Graphic: ATI Radeon HD 6850
But from the day of purchase i started facing the problem: "Display Driver stopped responding and has recovered"
so i format the pc, then again same error,i had updated driver and updated bios and tried a lot of things but nothing helped, so finally i complained to seller and got replace my graphic card and now everything is fine, So every one else having the problem, try replacing the card.