***Neither a teacher nor a native speaker.***
1) I was sleeping on my bed when my cat stepped on my stomach. :tick:
2) I was pressing the operation button of my computer last night to turn it on. :cross:
3) An elephant was pulling a tree out of the forest. :cross:
4) Ahmed was panting after he won the running race. :?:
5) The fans were yelling on the magician after he made a fault trick. :?:
6) Tom was donating his servings to the Pakistanis who afflicted with the flood calamity. :?:
2. I pressed the operation button of my computer last night to turn it on.
3) An elephant pulled a tree out of the forest.
4 - 6) Not sure, but I guess you don't need the progessive form there.
Look, the principle of the progressive use.
We normally use it to connect to operations that happen/appear simultaneous.
Your 1st sentence is a great example.
Action 1: You are sleeping.
Action 2: Your cat steps on you while you are still sleeping.
It's logical that your PC goes on when you press the button.
You can say:
My PC broke last night, and I have the feeling it was my fault, because:
I pressed the button while it was thundering.
Normally, when several actions happen one after the other, you don't need to use the progressive version either.
What did you do yesterday?
I got up, then I ate, and I later I went to a friend.
That's why sentence 5 should be:
5) The fans yelled (or laughed) at the magician after he made a fault trick.
These two "operations" don't happen simultaneous.
I hope some other members will help you as well, because it's a hard topic.
Cheers!