SP3.0 also installed "PDMWorks Workgroup" into an ACAD installation (complete with non-optional splash screen) without asking. Very annoying.
Since it took me a few minutes to figure out how to get rid of it, here's how: Find the acad.rx file, edit it in notepad. Delete the line that references PDMWorks. If that was the only line, delete acad.rx becasue it causes longer load times, even when empty.