You need to do a few things to determine why you are not getting sound from your speakers.
What sound chip ( or card ) do you have?
Open a konsole and run the command as root 'lspci' and look for your sound card information. It may not show up there if is onboard, and not connected to the PCI bus. All command are without the quotes.
Next find out if you have a KLM loaded (KLM-kernel loadable module). In windoze you call it a driver.
Once again, as root run the comand 'lsmod grep | snd' Post the results of the commands. If you have a loaded module, then you may only need to open a mixer and make sure the volume is turned up, and not muted.
Does this happen for installing linux or for some other reason???
Hardware detection in linux is improving all the time. With that said, not all hardware is detected. In such cases we have to find out what the hardware is, find the module, and load it using the command 'modeprobe modulename' This is just part of a learning curve you will go through on any linux system.