Legacy audio drivers

Hello,
my laptop was working properly before i played dvd.after playing dvd when i tried to watch video songs i could not watch it properly as there was no proper sound ...it was scrachy...same case with the audio songs....i thought it may be bcz of virus problem...drivers might hv corrupted....bt i cant even download audio drivers ....
if this sound problem is bcz of virus or smthin else plz help me on this....and plz tell hw to download drivers if there is problem with the drivers....plz help me...............ma laptop is 3000 c200 lenovo....