need help from a pro

I have just installed a new graphics card (leadtek FX5600 256MB)and when I run dxdiag the AGP texture acceleration is not available. I hasve tried reinstalling dx9 and also tried installing older drivers and new ones as well, also installed the chipset drivers. As of yet i still do not have the texture acceleration available. Can someone please give me some directions on where to solve this issue, as my pc runs slower than it did with the Ge-force 3 ti500.

OS- winxp pro
Abit NF7s with nforce chipset
1GB ram
oh and the FX5600 🙂

please please help!!!!!!!