Is there a way to remove this unresponsive window of Action Center program in windows 7 without a restart?

The following window is not disappearing at all. I don't want to do a restart or shutdown. Also, It persists even after a sleep.

My issue is a persistent Aero window that wouldn't close. nothing related to backup.

How to remove it ? is there some process or service I can kill ?

A small window of action center program is stuck:

This window/tile will be 'hosted' by the explorer.exe process.

I would suggest the following actions:

1. Open up Task Manager
2. Find explorer.exe
3. End Task on explorer.exe
4. From the File menu in Task Manager, select Run new task
5. Enter explorer.exe and click OK

These steps will restart the explorer process, and the windows it's hosting.