My webcam is not working

Hello,
My dell inpiron 1525 s abt 1yr old and i've formatted it once due to virus attack.Now i'm not able to get access to my webcam.i've tried reinstalling the driver from cd,but it was working.and i also get some trouble while playing VLCmedia player.A text box appears in the middle saying that windows has encountered a problem and needs closing.'ll this problem be due to virus?Is there any solution for these problem? plz help.