Problem with New graphic card

hello friends,

i brought a new graphic card and installed it in my PC. everything went fine for 3 days, i have played all the high end games without any problem but after 3 or 4 days...the monitor started going into standby mode and some times it shows some gibberish colors on the screen.

Below are my PC specifications.

LG 17" CRT monitor
Processor : Dual core 2.88 GHz.
MOBO : D102GGC2.
ram : 2 Gb DDR2
OS : WINDOWS XP SP3

Graphic card : NVIDIA GT 440 - 1 gB (DDR3) Purchased in September 2011.


I changed the screen resolution from least to max and tried in each instance but with no luck.
Formatted the system and installed a new os but that did not help either.
I checked the temparature using Everest software and it showed around 39-40 C always.


Does any one have any inputs on this..