Refer Symantec support to "Dell Solutions and the Symantec Management Console"
"Question: I no longer want to use Dell solutions or I see issues after installing them or I uninstalled Dell solutions and now see issues occurring elsewhere in Altiris. How can I successfully remove these from Altiris?
Answer: Use Symantec Installation Manager to remove all Dell solutions and components. If there were issues caused by any Dell solutions, this should resolve them. If not, please contact Technical Support to obtain an special clean-up script and reference KB TECH159959."
"http://www.symantec.com/docs/HOWTO59488
Although, if it's not too painful, a rebuild when you go to 7.5 will clean lots of stuff up.