GTA 1V won't run

Hello,
First of all I came up with DD3D50 error,so I re-installed Direct x9, then after the re-installation it now comes up with shader 3 or above required! ...... I have been unable to play this at all! It goes to play,screen goes black,then now comes up with shader 3 or above required!

I have an ATI Radeon 9960? graphics card....... this is the only game that I have had problems with!! I have an AMD3000+ graphics,lots of hard drive space,1 gig ram......... Please Advise how to get the game to run!

Thank you...
Terry.