Agree with make back ups from now on..... I'm sorry to hear you've just learnt the hard way
If your reinstalling the PC that crashed then 2 things.
first, unless you've had to replace the hard drive then most of the stuff would have been retrievable without too much effort or cost (and a fair amount may still be but stop installing stuff now if you want to get the stuff back!)
Second, you need to download and install the sound card drivers for your computer, if it's a brand name computer then the makers website will have the drivers.