Problem with new card!

[kentcol]

My system:
Alienware P4 3.4GHZ 950 D 4MB L2 Cache S775 Processor
ASUS P5ND2-SLI Basic NForce4 Motherboard
3 MB DDR2 PC4200 Memory
ASUS AUDP5ND RealTek On-Board Audio Sound Card
650 Watt power supply
Windows 7 Home

I have currently installed two(2) XFX NVidia GeForce 7800 GT 256MB PCIE video cards. I recently bought one NVidia GTS 250 1024mb card. I have tried to install it twice and every time I do, I get constant freezes and lock ups. I disabled the SLI, unistalled drivers and re-installed but always the same result. Any ideas?

 

[kentcol]

Actually, the last time I tried it I still had XP. But no, installed and loaded new drivers and on boot up usually froze after start up.

 

[kentcol]

Ok, I have Win 7. I will try that and let you know. I did that on XP and had same result though.