I assume you have the install files and reg codes for all voices and the SynthV1 program install code safe somewhere, several v1 voicebanks are no longer available from the suppliers so may be irreplaceable.
As @Asinine says, deactivate evrything prior to the windoze install.
Reinstall Eclipsed Sounds Voice banks on new PC - Synthesizer V Studio - Dreamtonics Users Forum
How to deactivate - Synthesizer V Studio - Dreamtonics Users Forum