Windows saying hdd is cd rom

Does the drive itself work when you copy files to it?

If it does then your icons just got messed up in some way, reboot your pc press f8 select safe mode, when you get to the desktop reboot normally, doing this helped me a lot in the past when i had similar issues

A model number would help immensely.

For example, some Western Digital models will enumerate as a Virtual CD (VCD). This is because they have integrated SmartWare software.

HP's SimpleSave drives also behave this way.