|You don't need a CD.|
I'm assuming you have not dropped the external drive and damaged it.
If the drive is new, or if it's partition(s) has (have) been deleted, it (they) will not show up in My Computer or Windows Explorer until it has been software partitioned and formatted using something Windows recognizes -e.g.you can use FAT32 or NTFS and format it in Disk Management in Windows
Troubleshooting USB device problems including for flash drives, external drives, memory cards.
See Response 1:
Check that out first.
Rarely, not all the ports on the back of a desktop case may be able to supply 500ma each.
If you have a desktop computer, Note that I answered a Topic on this site where a guy had an external drive, which does require the full 500ma, connected to a port on the back of a desktop case - it would not work properly when a webcam was in the port next to it, but it worked fine when the webcam was unplugged. Ports on the back of a desktop case often have two ports connected to the same USB controller module that are ports one above the other - you could try connecting the cable to one of those and leaving the other un-used.