Insallation DVDRW

Hi there,

I have a Dell 4500 Dimension Desktop, Windows XP Home Edition, 512 Gb Ram.
I removed the CDRW that came with the computer, and installed an LG DVDRW.
When I turned the computer on again, the E drive had disappeared.
I tried various things:
Reinstallation.

Removing the D drive cables and replacing them, same with E cables, and restarted computer each time.

Sometimes the D drive is reading the CD that is in the E drive, and sometimes what is in the D drive.
They seem to be both trying to take over the D drive.
When I install the D drive first, it reads that fine.
Then when I try to install the E drive it either takes over the D drive or doesn't start at all.
Can you help me?
Did I forget to do something?

Thank you,
Sincerely,
Peter