I have Sony DVD ROM Drive and LG CD/RW Drive installed on my system. When I turned on my system on 14th July at 2:10 P.M., I found that there was no drive in "My Computer", except four partitions of Hard-Disk and 3½ Floppy Drive. When I opened the Device Manager, it marked a yellow coloured "!" on both the drives. I tried to uninstall the drives and then Windows XP detected both the drives as "New Hardware Found" at startup and installed the drives with own drivers. But it did'nt work.I tried to restore my system, but it also did't work. What is the cause of suddenly disappearing and uncompitaibilitity of drivers? How can I now install them?