Lost my cd and dvd drive from My Computer

[rockoreid1]

My cdr drive and dvdrw drive disappeared from My Computer. I cant use my drives. I checked the systems device and it shows a yellow exclamation point. It said that my drivers are missing or corrupted. I deleted them and rebooted XP. It is still the same. I even uplugged my drives from the computer and than rebooted. Than I plugged them back in, than rebooted. They still are gone from My Computer and they still show a yellow !. I think i need some new drivers but cant load the disk because they don't work. I cant find any from the internet. I have windows XP home, my computer is a emachine T3414. The driver are lite-on combo SOHC-4836V and lite-on DVDRW SHW-160P6S. What would cause them to disappear from MY Computer

[GX1_Man]

First off I deleted your two other identical posts. One is enough. Thanks.

What happened prior to all of this? Any kind of changes to hardware/software/settings are suspect.

Basic drivers for these devices are built in to Windows. What version, and what service pack? How long was this running fine before this?

What kind of malware protection is being used? Any unusal activity there?