The E-Mu Proteus VX is a software implementation of the Proteus 2000 synthesizer. It can be used as a standalone application or as a VST instrument.
It was originally released for Windows XP and may or may not work properly in more recent versions of Windows.
The software was later discontinued and an unlocked version with the Proteus X v2 ROM bank was offered as a free download. It is available here: Creative E-Mu Proteus VX. We have also made a copy available below in case that page ever goes offline.