[Wine] Ubuntu crashes when gaming

[bouc-hemisphere]

Hello, 

I am a french Ubuntu user since a few weeks. So, please excuse my English and my Technical knowledge. 

I've got a problem when I play games with wine : my computer crashes and reboots. 

I tried two games : wow and oblivion. 

Here is my config : 
ubuntu 9.04 « Jaunty Jackalope » 64 bits + Ext 4
Graphic card GeForce GTX 260 PLUS - 896 Mo DDR3
INTEL Core 2 Quad Q9400 - 2.66 GHz
3 x (KINGMAX DDR2 PC2-8500 - 2 Go)

I use the last wine stable version. 

Could you help me ?

Thanks a lot.