First, we don't "bump" threads on this forum. Keep in mind this is a users helping users forum. If a user has an input they will post it.
I assume your E510 is the same as mine and came with the basic SigmaTel integrated (on the motherboard) audio.
As you have tried installing, we find that many skip the Intel motherboard chipset drivers during installation and that MUST be installed BEFORE the sound or the sound drivers will not install or work. Also you must have the Dell supplied drivers as we have found non-Dell drivers will either not work or not work correctly.
It's rare that the sound chip on the motherboard will quit working, most likely it's a driver and/or chipset issue. If the chipset drivers were skipped, install them, restart the PC and then install the Dell SigmaTel Drivers. The Dell drivers downloads for the E510 and Windows XP are HERE
FYI the correct and required install sequence for a Dell is (1) Install Windows (2) Install Dell Desktop System Software (3) Install Intel Motherboard chipset drivers (4) install device drivers including Video, Dell sound drivers, Ethernet, etc.
Finally, an add on PCI (not PCIe) sound card is an option. I have a SoundBlaster Audigy SE installed in my E510 and it works well. The only drawback to ANY add on sound card is that you will lose the front panel headphone and mic jack capability, due to Dell's Proprietary and undocumented front panel wiring and connector.
I am not a Dell Employee
Dell forum member since 2002
Home Built PC with Gigabyte GA-Z77X-UD5H motherboard, i7 3770 CPU, Windows 7 64 bit Home/Win 8.1. SSD drive. Sonar X3c 64 bit Recordng Software.
Member of Nashville based R.O.P.E.