After effects wont open

Without exact system info and screenshots this isn't going anywhere. Generic "This doesn't work" posts are not in any way useful.

Mylenium

If it's in the task manager and it won't open, it means the process is stuck. You should actually kill the process from the Task Manager and then relaunch AE. Alternatively, you can restart your computer and everything should launch properly. This might be the better solution if you're also using Dynamic Link, as that process might be stuck, as well.