Thread:Project:Support desk/old mysql database resulting in Cannot contact the database server/reply (5)

So in fact your MySQL installation is broken and mysql_upgrade.exe does not tell you anything helpful as to why it fails.

If you have nothing else in the MySQL server I guess this is the case as it is broken anyway), then I would do the following: Use the old MySQL server to export your database. Result should be a database dump file. Then set up the new MySQL server just doing a new install. This should give you a working MySQL server without having to upgrade anything. Afterwards import your DB again from the dump.