Had to reformat C: on Dell Dimension 3000. Now can't get any sound. Tried to download drivers from Dell but it comes as an application and I can't open it. Any advice please?

Most of the Dell driver downloads are .exe files. They are self-extracting executables (much like a ZIP file). You need to first double-click the downloaded file and when the extraction window pops up, make not of the directory that the file is going to extract to (usually c:\dell or c:\drivers). Once you noted the directory, continue with extracting the files. Then go into your device manager (control panel, system, hardware, device manager) and find the sound device that is either disabled or not loaded properly (usually will have a yellow exclamation mark next to it). Double click the device and "update driver". When prompted, point to the folder that the files extracted to earlier, and then the device should load properly.

Some Dell drivers include a setup.exe file, but most of them follow the above-listed format.