Im getting this msg

GPUGRID|Message from server: Can't use NVIDIA GPU app for Full-atom molecular dynamics: Your GPU lacks the needed features

And as far as Im aware my 8800GTS will run it. got all the latest drivers and so forth. any ideas? A sticky on this would be good too

Only if GTS512; if it's 320/640 then no dice;

GPUGrid now only supports Compute Capable 1.1 and above (1.3).
Anyone with a 1.0 Compute Capable card will not be able to contribute!
Unfortunately that excludes the following cards,
GeForce 8800 GTS, 640MB, est. 41GFLOPS (compute capability 1.0)