ATI X1600 Pro Question

I purchased a new computer a while back mainly for other things and didn't get a video card with it because I wasn't planning on simming for a while. Yesterday, I bought a ATI X1600 Pro PCI Express card and immediately installed the drivers. After tweaking it a bit with antialiasing and anisotropic settings, I was ready to fly again. After loading up FS, all my edges were jaggy (even after I turned all those filters on....keep in mind, AA is off in FS). So I turned the filters off and then on again. Finally, everything was smooth. I closed FS to install some different aircraft and scenery and loaded it back up. The jagged edges were back.When this card works, it's nice and seems fairly smooth. Does anyone have any clue why this is happening? I didn't install the drivers from the disk. I went directly to ATI's site to download the new drivers.System Specs:PD 2.8 GHZ2 GB RAMATI x1600 Pro 256 MB80 GB Hard DriveWindows XP Pro w/ indexing service turned off