After many attempts, I was finally able to get my ATI Radeon HD 2600 AGP working in Windows 7 32-bit using the method described by Jack006 here: x1950 agp, nforce3, x2 athlon 4000 -problem
I have an MSI K8N Neo2 Platinum (nforce 3) with an AMD Athlon X2 4800+ (dual core). I also ran "bcdedit.exe -set loadoptions DDISABLE_INTEGRITY_CHECKS" to disable driver
signing. I used the latest Catalyst 10.6 driver hotfix. I was not working until I ran the Nvidia 5.11 GART driver.
Now I have a CCC icon in the Windows 7 system tray and I have dual monitor working.