Q: Removed FCE but still something on the computer

Couple of things:

If the version you are trying to install is an upgrade version, then you do not need to install the original version first, but you will need the original (full) version serial number. You will be prompted to enter both, the full version serial number and then the serial number of the upgrade software you are installing.

Removing all traces, so the FCE installer will work correctly can be difficult. You can download FCS Remover from Digital Rebellion (free) and it will do the work for you:

http://www.digitalrebellion.com/fcsremover/

What OS are you installing on?

MtD