Do this very important!!
Most viruses uses the autorun.inf to get itself infected on your computer. Autorun.inf is a small file that instructs the windows os to do when the CD is inserted into the computer. In genuine cases , it runs a setup in case of a Software Installation Disc. In the other case it may run a virus and gets your system infected. All you got to do to get the virus is put the CD. Same is the case for Mass Storage Devices like Memory Sticks, Pen Drives, Flash Drives etc.
So Disable your Autorun now
Services\Cdrom\Autorun Change from 1 to 0
To disable Autoplay of all drives
Start > Run > gpedit.msc
Enable : Computer Configuration > Administrative Templates > System > Turn Off Autoplay