wow, thats the longest sentence I've ever seen.... periods, use em
Anyhow, sorry you had me confused, too. The main drive is normally not considered the cdrom. Threw me off there, when you said the main drive wouldn't load and yet could goto start, run, etc... was like... "ummm.. huh??". Anyhow, incase you are for some reason being blocked behind a firewall or something here is the registry editing steps listed above by codes:
Restore Missing CD or DVD Drive
Reports have filtered in that CD or DVD drives will suddenly cease to exist in XP systems. Most often this has been reported in conjunction with program installations and Windows upgrades, but it has also happened for no apparent reason. This tweak will restore the missing drives after a reboot.
[Start] [Run] [Regedit]
Registry Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class
Key Name: {4D36E965-E325-11CE-BFC1-08002BE10318}
Value Data: [Delete All Value Data from UpperFilters and LowerFilters]
Note: Do not delete the Key or the Multi-String Values. Delete only the data values.
Exit Registry and Reboot