Had the same problem on my Dell GX620 after doing a reinstall of XP
Eventually fixed problem.
After install I installed an Nvidia graphics card; this change the sound driver from SoundMax to an nvidia driver. At this point lost sound; and any reinstall caused the no ADI codec error.
2 easy solutions; either change the driver been used in the control panel - sounds or install a 3rd party driver such as the Omega drivers
Hope this helps
