Graphical error installing windows 7

[Cpucomputer]

the computer has a graphical cracked green screen with multiple other colors, this happens during the install and then I cancel the install and windows xp comes back in normal. Its a dimension 2400 512mb ram, pentium 4. I have installed windows 7 os on other computers with the same amount of ram so I don't think its a ram issue even thoe it does not meet the minimum requirement. I don't believe its a driver update issue, please help me in this problem, thank you.

 

[cboucher]

The onboard video hardware may not be compatible with 7.

 

[Cpucomputer]

The onboard video hardware may not be compatible with 7.

My friend who had a custom built computer with a nvidia graphics card 8800gt had the same problem.
I have a 8800 and 7 is installed on my computer. So Its baffling really.