Don't have the answers to 2 or 3, but I have similar problems with my ATI card (Radeon 9600) from time to time.
It refuses to acknowledge thats its capable of HW3D. Sometimes my PC won't even start up, and when it does, dragging windows around the screen it only updates at about 3fps.
Reseating the graphics card in the AGP slot sorted it, for me.
Overall, though - it sounds to me like you need to take the PC back to where you bought it from and get them to fix it and if they say they can't they you need to be looking for a refund, either directly, or through trading standards. I'm guessing you haven't had it very long?
It refuses to acknowledge thats its capable of HW3D. Sometimes my PC won't even start up, and when it does, dragging windows around the screen it only updates at about 3fps.
Reseating the graphics card in the AGP slot sorted it, for me.
Overall, though - it sounds to me like you need to take the PC back to where you bought it from and get them to fix it and if they say they can't they you need to be looking for a refund, either directly, or through trading standards. I'm guessing you haven't had it very long?