What do i do after finishing the installation of ATI Radeon 5800?

I was using ATI RS740, and i just downloaded and installed ATI Radeon HD 5800. There was no error during and after or before the installation. But when i opened dxdiag and click on the display tab, the graphic card using is still RS740. Help, please?

Go into control panel then system and device manger. Click your old graphics card go to properties and change it to disabled. (that is if your old card is an integrated one)And obviosly make sure that your monitor is plugged into your new card before or you wont be able to see anything on the screen.

Enter BIOSIn the Advanced Section, change Primary Display to PCI ExpressSave & Exit BIOSShut downConnect Monitor to ATI HD5800Restart Install driver when new hardware is found.