Troubleshooting PC Crashes with 1 gig of ram but not with 512mb

PC Crashes with 1 gig of ram but not with 512mb

Processor: Name and speed AMD /sempron 2800+ MMX 3DNow ~1.6GHz
System Memory RAM 1008mb RAM
Windows Version XP Professional 5.1 build 2600
Free Hard Disk Space: 190gig
Total Hard Disk Space: 200gb
DirectX Version: 9.0c
Display Adapter: GeForce NVIDIA 128 compatible 128MB - on board
Display Driver: version 6014.10.8205,date 24 Jan 2006, Name Number
Approximate Total Video Memory 128mb
Game Detail Sims 2 DVD. Expansion packs various pets, university, family fun stuff, glamour, highlife)

Nature of problem
I have 2x 512 DDR2 memory on the above motherboard. It works fine but when I try to launch Sims2 the sims first screen appears then disapears, after a few seconds the PC crashes - blue screen. The blue screen includes a stop code: 0x0000008E 0xc0000005, 0xVFABAFCB, 0XF4738B88, 0X00000000 and then a the bottom of the text says Beginning dump of physical memory, physical memory dump complete, which maybe hints it is simething to do with the memory???
So I take out one of 512 memory it works fine. I have also tried 1gig stick DDR2 memory and sims still crashes. I have read through this forum researched to death and cannot find what the problem is. I've followed all the advice under similar problems like removing all expansion packs, checking dxdiag, turning off background processes, tuning of virus s/ware, changing ram slots, swopping the ram, stopping the video... all with the same result. Sims2 is the only game I have on the PC, it is new and not been on the internet yet. I'd like to use the 1 gig or more in my pc for other things but it seems sims2 doesn't like more than 512mb. I'm no techy... Can anyone help??? I'm at my wits end!!!!!

 

PC Crashes with 1 gig of ram but not with 512mb

Tried memtest overnight something like 9 hours. Up to that point everything passed.
I also realised there is more info on the blue screen message after PC crashes, that I had not taken into account:
***nv4.disp.dll - Address BFABAFCB base at BF9D3000, Datestamp 43d6e61C.
According to dxdiag nv4.disp.dll is the main driver for the onboard graphic card (Nvidia GeForce 6100/NVIDIA nForce 410 MCP). I think the dirvers are the latest. Could it be that its the graphic card that doesn't like the 1gig ram using sims2? Still not sure what to do next..

 

Thanks matey, think i'm getting somewhere. Do you think if i insert a seprate graphic card (not nvidia), will change the driver? I may have to do this.