When your CD/DVD drive suddenly disappears (Windows XP)

What you need to do:
1. Click START -> RUN
2. Type REGEDIT and press enter or click OK
3. When REGEDIT starts, open up the following folders HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318}
4. After clicking on {4D36E965-E325-11CE-BFC1-08002BE10318} you should see two settings on the right pane:
"Upperfilters"
"Lowerfilters"
5. Click on each of them, press DELETE and click YES to confirm
6. Close REGEDIT, shutdown & restart your PC

It is a quick and easy fix. Back up your registry first just in case you need to restore it after the modification.