[Newbie]No screens found

[Elizabeth Smith]

Hi I am totally new to this but here goes.   I have a duron 1.2 gig with 256 meg of ddr ram and a GeForce2 mx400 64 meg card.   When i try to load X it dies with a error stating   Screens found but none have a usable configuration   What the hell does that mean. and how do you fix it ?   thanks