I need the audio driver to gx270 dell

Visit Dell Support and select "I'm looking for drivers and downloads". Select by model your product, Optiplex GX270, and then select your operating system. Click the + beside Audio to expand the list and select the driver for whichever audio hardware came with your system. If you don't know which hardware your system has, start over and select by service tag and enter the tag on your system to get results specific to your system. You can also look in the Windows Device Manager.