How to know what drivers I need and where to get them?

this is kinda a long story
I got my computer about 2 years ago from tiny computer comany.
Ever since i got it for no reason it turned itself off. I put up with it untill now but recently decided to install windows from a different disk as i herd that there were some problems with the software installed on them by tiny
Now ive realised that the software for everything was on the bloody disk of tiny so now i have no software for my sound card. i downloaded the software for my graphics card but i knew what model it was, i dont even have a clue what make my sound card is! anyone know what i can do?
any help would be brilliant! thanks

Go to ‘Start’ -> ‘Run’ and in the box, type “dxdiag”. This will run a Windows diagnostics program that will report what sound card and devices are installed.

Failing that, visit the Belarc website and download their free PC ‘Advisor’ program. This will also look at what you have installed.