In the light of the answer by @harrymc I'm not sure I've understood the question but I'll plough on anyway.
If you have a lot of tasks open (including Task Manager) you can use Alt/Tab to see a list of everything that's running and bring a selected one to the top.
- Press and hold Alt
then, whilst still holding
2a. Repeatedly tap and release Tab to cycle through the windows. When you're on the one you want, release Tab and it will come to the top.
2b. While hold Alt, tap Tab once and then mouse-click on the one you're interested in. It will come to the front.
2c. Examine the thumbnail you are interested in - it will show you the current state of what's running.
You can also experiment with WindowKey plus Tab.
There are other shortcuts depending on what exactly you are trying to do.