Having it cleaned up by the antivirus (activescan does also kill them) and a restart should fix it.
Anyway, analyse it harware-wise:
Try another cd-rom device. If that does not work it could be a failure in the motherboard. If this is the case, change the position of the device (any of the free IDE cables: primary slave, secondary master, secondary slave).
If this didn't solve it you should try another motherboard (but let that to the technicians
)