Previously I was running Backup Exec 12.5. I installed 2010, entering all the relevant licence keys, then rebooted at the end. It took a long time to reboot the server: it spent 5-10 minutes sitting at the "Applying computer settings" stage. When it finished, I logged in and ran LiveUpdate. It found three patches, and downloaded them all, but they all failed installation. I then found that I couldn't run the main program because two of the services wouldn't start:
Backup Exec Agent Browser
Backup Exec Job Engine
When I tried to start them manually, it just said:
"Error 1053: The service did not respond to the start or control request in a timely fashion."
When I spoke to Symantec, their tech support guy spotted the problem (via a WebEx session): the main "Backup Exec Server" service had a status of "Starting" rather than "Started". It turns out that this is a known problem (something to do with the firewall service), which has now been fixed, so I just needed to install the latest patches via LiveUpdate. Unfortunately, that didn't work, as I mentioned above.
This is also a known problem, with its own workaround: I had to remove the licence keys (putting it into the "60 day trial" mode), then run LiveUpdate, then add the licence keys. So, I removed the licence keys (by re-running the setup program), but the services still displayed the same status. I used Task Manager to end the "beserver.exe" process, but the "Backup Exec Server" service still said "Starting". We checked Task Manager again, and that process was back in the list, which was rather odd. So, I clicked "End Process" again, and it disappeared, then a couple of seconds later it reappeared. That's weird, but what's even weirder is that all the Backup Exec services then showed their status as "Started". I.e. the way to start the services is to end one of them. Hmm.
Anyway, after the services were all running I was able to run LiveUpdate and install the patches. I ran the setup program again to add the licence keys, but it told me to reboot first so that I could complete the previous setup. Fortunately, the server rebooted much more quickly this time. After the reboot, I ran setup again and entered the licence keys, and now it all works fine.