You will have to go to www.support.dell.com go to downloads choose your system see if theres audio drivers for windows 7.
I just went from Windows XP to Windows 7 today on my Dell Inspiron 530. Used easy transfer from microsoft, had no problems updated all drivers and installed all programs. I now have a noise coming out of my speakers. The best way to describe it is 2 seperate tones coming out a spaced interval continually repeating.I have gone into device manager and checked for updates on drivers and I currently have the latest.