Lately I notice that every time I insert a DiskOnKey or a disk, the AutoPlay/autorun doesn't appear. I also notice that when I click on the disk drive in My Computer window, I will get directed to the explorer view of the disk and the autorun doesn't engaged.

It is especially annoying when I insert a disk for some installation and I have to search for the setup.exe file…

After googling for a while I found this article:
Fix Windows 7 AutoPlay Dialog Box Missing or Not Appear, Display and Pop Up

Apparently, some programs you install decide to disable the autoplay option. VMWare player was the cause in my computer.

After running all the steps described in the article, all came back to normal…