CD-Rom and Writer disappeared

A friend of mine accidentally deleted some drivers so now the CD-Rom and the CD-Writer can’t be seen in My Computer. I checked the hardware list and it shows both of them with the yellow and black exclamation mark icon. I uninstalled both the devices, restarted the comp, and added the hardware again. It searched for the devices, and already found software installed for them, and didn’t ask for any added installations. Now the software it accepts is the set of corrupt drivers that are installed on the computer. Can’t seem to remove this set of corrupt drivers. What do I do?

Please mail me at identities@rediffmail.com and let me know. Thanks a ton,

Kamal