HI!
Can someone please help?
I changed the type of line of one layer a few times and then when I hit on 'Layers Properties' icon once more, it freeze and a message stating that there is a software error and it close all files and applications. I tried to shut down and reopen my computer, open a new file, call out an old file and when I hit on the same icon, the same thing happen again.
Please help!
Thank you!

Try opening the drawing, under file /drawing utilities, purge the drawing then run audit saying yes to fix problems. If its still happening using the windows command  not the autocad one,  copy and paste the whole drawing into a new file.

Hi Peter. M
Thank you for your suggestions. Currently I'm able to continue with my work by not clicking on that button. I will try your method after I had completed my work because I'm afraid of loosing my entire file. Will keep you updated once I try it. Thanks!

Do a save as first with a slightly different file name so that you have a back up should all fail.