[Closed] MS Project help

I am after a simple way to weight a task in MS Project please.
The task is compute intensive rather than duration intensive so when I set it to 100% the gantt says that the project is only 44% complete when in reality (if I take into account user and cpu usage) it is 79% complete so I need to somehow weight this task. Can I do this and if so how please?
(In simple terms - most of the online forums describe a really complicated way and there does not seem to be one way). I do not want to add user resources to the project because then the project will jump to 3years long rather than 6 months.
Thanks