Soundcard and CDROM not working properly

I have a windows 95 OS. the problem is my pc cant detect my soundcard, i tried intalling it to my friend’s pc and it worked well. Another thing is my CDRom, everytime i place CD on it, it will just eject my CDs. Ive been using this PC for more than two years already and its been working fine,the problem started after windows was reinstalled due to an “illegal operation” error message, i cant figure out what seems to be the problem, can i ask some help? thank you very much.