ok i tried that on mine but im running vista so i used windows xp sp2 in compatibility mode an it still dont work

Because the driver is a /XP/Vista driver you don't need to use compatibility mode. The problem with Vista is that it requires some other files to be be installed before the Sigmatel audio driver, but Dell does not support Vista on the D and so the required files are not available. (It does not matter with Windows 7). The installation method for Vista is:

> First remove the installation you have done so far. Go to this location on your hard drive   c:\dell\drivers\

Expand all folders and sub-folders there. Delete all folders that have a sub-folder named "WDM". Those will be the audio driver folders and it is safe to delete them. Restart the laptop.

> Download the Sigmatel audio driver R (or re-use the package you already downloaded if you still have it).

Extract the files (unzip or unpack) but cancel the installation process. The files will unpack to a folder on the hard drive at c:\Dell\drivers\R, and that folder will have a subfolder named WDM.
Open the Device Manager and expand System devices near the bottom. Find the PCI Device entry with a ? next to it (or if that is not there then look for "Multimedia Audio Controller") . Right click on the name and select "Properties", then choose to update the driver. Choose to manually find the driver and don't let Windows look for it. Browse to c:\Dell\drivers\R\WDM.

When you restart the laptop Windows will detect some new hardware and one of them will be the Sigmatel.