Welcome to Windows SevenForums. Your system is a socket 478 which means the hardware is very old.
Which version of Seven are you trying to install? 32 or 64 bit?
Your card has to use legacy drivers
, so try installing them using the method in this thread through your device manager. Install AGP Drivers for HD 3850, 3650, 2400 PRO
Here is AMD's driver
download page for Vista 32 and 64 bit which will require you to install it under compatibility mode Compatibility Mode
Driver download http://support.amd.com/us/gpudownloa...4&lang=English