Graphic Cards Questions & Answers

I purchased a new laptop dell xps l401x 4 months ago.last month, accidentally the water was spilled on my laptop after this mother board has been replaced.
after this replacement i face problem in each game e.g.
fifa 11
hot pursuit
age of empire 3
street fighter 4
every games runs smoothly in first minute, then screen gets flickering or freezing slowly.
i updated all the graphic drivers, bios, even tried dell factory restore
even due to this problem my motherboard has been replaced again but this not worked out my problem.
all thes games worked very well before motherboard replacement....

following are my graphics card details:

[Display]
Operating System: Windows 7 Home Premium, 64-bit
ram : 4gb
DirectX version: 11.0
GPU processor: GeForce GT 425M
Driver version: 275.33
DirectX support: 11
CUDA Cores: 96
Core clock: 560 MHz
Shader clock: 1120 MHz
Memory clock: 800 MHz (1600 MHz data rate)
Memory interface: 128-bit
Total available graphics memory: 3807 MB
Dedicated video memory: 2048 MB DDR3
System video memory: 0 MB
Shared system memory: 1759 MB
Video BIOS version: 70.08.19.00.10
IRQ: 16
Bus: PCI Express x16 Gen2

some one please help me out....:(