Of course! It's better if you install Firefox before uninstalling Internet Explorer. Open the Control Panel > Programs and Features > Turn Windows features on or off, then uncheck "Internet Explorer" line, accept the warning message and click on OK.

It is one thing turning off IE features but do NOT attempt to uninstall it.

IE is closely linked with the Windows Explorer, and may well be essential for some features. Besides which it is always good to have backup browsers in case the default one fails for any reason.