Page Fault in nonpaged Area

Firt of all, excuse for my english. I can read, but I cannot write. I am live in Brazil.

My computer is showing a blue screen when I play Fifa Soccer 2005 and other games (I had install the same games in other computer, and works well). Sometimes the information of blue screen change. Another day it is showing:

Driver Irql not less or equal
[....]
smwdm.sys
[....]

I update my sound drive and the problem was resolved. But, in the next day, the blue screens appears again, but with another information:

Page fault in nonpaged area
[...]
nv4_disp.dll
[...]

I update my video drive and the problem don't resolved. I feel that after the update the blue screen appear more fast.

So, what I must to do?

Can anyone help me?

I make a search in "google" and the opinions are much variants.

My computer is:
AMD Sempron (TM) 2500+
Windows XP (SP 2)
GeForce FX 5200
512 Mb RAM (two combs)

Thanks,
Felipe Sabino
MSN: felipe.spurgeon@gmail.com

I received another blue screen now:

Stop: 0x0000008E (0x0000005, 0xBF824DE0, 0xB1DEEB18, 0x000000000)
[...]
Win32k.sys - Address BF824DE0 base at BF 800000. Data Stamp 43446a58.
[...]