HELP! GeForce 8400 GS Problems

[ACER4910]

I just bought this GeForce 8400 GS and when I come to install the drivers windows locks up when loading the start-up screen please help I am despirate for a solution
It does this with any Nvidia driver with other cards aswell
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My PC Specs
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Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 3 (2600.xpsp_sp3_gdr.100216-1514)
Language: English (Regional Setting: English)
System Manufacturer: HP Pavilion 061
System Model: PS261AA-ABU m1250.uk
BIOS: Phoenix - Award BIOS v6.00PG
Processor: AMD Athlon(tm) 64 Processor 3200+, MMX, 3DNow, ~2.0GHz
Memory: 1022MB RAM
Page File: 806MB used, 884MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 9.0c (4.09.0000.0904)
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It uses a ATi Xpress 400 Chipset which I think is causing a conflict help anyone please!

 

[Slaymate]

You need to disable the On-Board Video in the Bios Setup.

 

[ACER4910]

It does not have on board video :/

 

[95BlackGA]

Just for future reference, there is no Xpress 400 chipset. You have the ATI Xpress 200P chipset.