i gought a 2nd hand dell dimension 4550 after my old pc went bang. i decided to reboot it to get rid of all his folders etc. however, after rebooting it my ethernet broadband nor my soundcard worked. (both worked before reboot). i put a new ethernet card in and it works ok, but still no sound. i dont really wanna buy a new card...

why are they not working?

it says cannot find hardware when i try and play music.