Phillip,
I posted a thread recently with a similar problem...
http://forums.veritas.com/discussions/thread.jspa?threadID=61032&tstart=0
Where did you get the 4.5 version of Backup Exec Desktop? I downloaded a trial version from a shareware site (cannot remember which one) and tried installing it but the installer complained that my Windows 2000 OS was incompatible. So I tried compatibility mode (Windows NT, Windows 98, Windows 95) and the installer still wouldn't install the application. If you could help me out I would greatly appreciate it.
Thanks.