If a customer's Vista PC crashes, how is the software recovered, and is it necessary purchase all software again?
If a PC with Vista software installed crashes, all software needs to be reinstalled, and if necessary a rehost of licenses is required. The rehost procedure is covered in Rehosting a Vista 5 License on the FlexNet License Server.
The TAC Vista 5.x software itself is free and available for download from The Exchange Download Center.
If the software licenses are purchased once, they are still available and no repurchase is necessary.
If licenses were locked to a hardware dongle, just reinstall the license file(s) again when installation is completed.
If licenses were locked to a Host ID and Host ID is changed due to configuration changes on PC, you need to login to https://schneider-electric.flexnetoperations.com and rehost the licenses to the new Host ID.