applications are in use?

HI all

does anybody know of a way to work out which apps are in use and which can safely be deleted. I am trying to prepare for upgrade to 6.5.2 and have no idea which apps might cause problems if i delete them. I obviously know which of my own applications are in use and which fast forward applications we definitely use. However, I have found in the past that the complex relationships behind the scenes in rhythmyx means that apps i wasn’t even aware we were using have caused problems for us.

so if anyone knows of a way to work this out, i would be grateful.