You can simply install 7.8x on the new machine and attach to the existing database via the database setup tool. If you would like to keep the existing patch files, you can certainly move them (the path can be identified via the 'Patch Downloads' tab of the 'Tools>Options' menu).
It may also be helpful to review the SQL Post-Installation notes within the administration guide to ensure that you have correctly configured the SQL permissions.
Thx. What are the ways the upgrade can fail, either at the console or Db end? Does it simply remove 7.5, then install 7.8, then attempt the Db upgrade to 7.8? The Db is backed up. Should something happen to the install of 7.8 (assuming the db hasn't been touched yet), can 7.5 simply be reinstalled? Should something happen to the DB, could the whole setup be dialed back to 7.5 by restoring the db then reinstalling 7.5? Sorry for the hassle, just trying to anticipate any possible miscues.
The installer will remove the existing version of Protect. Next, the installer will check for necessary components, and will install them if needed. SQL Express will be offered, and Windows SQL Server 2008 R2 Express will be installed and configured locally if selected. Once the installation has completed, the database setup tool will launch. If you select to connect to an existing database, the database will be converted at this time (if the database is from a different version of Protect, such as 7.5). If the database setup tool fails (i.e. the conversion fails, a connection to an SQL instance cannot be established, etc.), the installation will back out. The previous version will remain uninstalled.
If you were to re-install 7.5, you could certainly connect to an existing 7.5 database. First and foremost, it is important that you have purged any uneeded data from your existing database, and have created a viable back-up.
If you are having problems with the database conversion, you can certainly select to create a new database at the time of installation, and can always attach to another database (i.e. the existing database) once the installation has completed. The database setup tool can be launched from a shortcut located within the Shavlik Technologies program group in the Windows Start menu.