game freezing up

[Rellik]

some time ago i started having problems with daoc mostly but recently some other D3D games allso started getting these freeze laggs..
daoc loads up just fine but after like 10-15min the game freezes up for about 20-30 sec wich makes me go LD. all the indicators are green when this happends..
and when playing other D 3d games, lets take UT 04 for example.. this game freezes up after 5 secs.. and stands still for about 5sec then comes back to normal but after 5 secs the same thing happends..
some info about my system etc..

Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 1 (2600.xpsp2.030422-1633)
Language: Swedish (Regional Setting: Swedish)
System Manufacturer: Dell Computer Corporation
System Model: Dimension 8200
BIOS: Default System BIOS
Processor: Intel(R) Pentium(R) 4 CPU 2.20GHz
Memory: 512MB RAM
Page File: 191MB used, 1058MB available
DirectX Version: DirectX 9.0b (4.09.0000.0902)
DX Setup Parameters: Not found

Card name: NVIDIA GeForce4 Ti 4600
Manufacturer: NVIDIA
Chip type: GeForce4 Ti 4600
DAC type: Integrated RAMDAC
Display Memory: 128.0 MB
Current Mode: 1152 x 864 (32 bit) (100Hz)
Monitor: Dell M991
Monitor Max Res: 1600,1200
Driver Name: nv4_disp.dll
Driver Version: 6.14.0010.5672 (English)
DDI Version: 9 (or higher)
Driver Attributes: Final RetailRegistry: OK
DDraw Status: Enabled
D3D Status: Enabled
AGP Status: Enabled

got all the latest drivers for the gfx card and latest direct X.
didnt find any other info in the dxdiag that i thought could be usefull..