i use incredimail, and when i have removed it i have no problems.
go into your task manager and see if it is running in there. if it is end the task and see what happens.
my incredimail can be uninstalled from the add/remove programes tab.
if you cant find it try downloading incredimail free version, then uninstalling it again, just an idea.
its running from an installer, that would lead me to believe its set as maybe the default e-mail thingy and when u open the other one this one tries to install its self again or something. try downloading it again and tehn deleting it through add/remove programs