I improvised the following solution for the problem. It has so far worked very well:
Make sure that the antivirus and the wallfire are off.
1- I installed Adobe Flash on another computer.
2- Then I copied the following folders:
Adobe Flash CS3
Then I pasted the files in their respective places on the defective computer.
Then, I uninstalled the program from Control Panel (Of course, now with the file being copied in the way I mentioned, the uninstall feaure is available in the control panel).
Restart the computer
Install the program again.