Whatdo you mean with 'old acc'? Old gmail account in bluestack? Or account in whatsapp?
I removed whatsapp in bluestack and downloaded again. But it does not ask for new code. Just username and profile photo.
1) remove acc whatsapp
2) Uninstall whatsapp
3) reinstall whatsapp, download from 1 store, g store or android store, if before this you installed from adroid store then u must choose 1 store or g store.
2) Uninstall whatsapp
3) reinstall whatsapp, download from 1 store, g store or android store, if before this you installed from adroid store then u must choose 1 store or g store.