Inability of Winamp to register some global hotkeys may come from many reasons, usually when other programs already have registered the exact same keyboard shortcuts. However, here is an additional reason you may ignore and you should try in case other solutions won’t work.

I was browsing an incomplete movie with VLC, when a blank part of the movie appeared and I had to terminate VLC. The program was closed, but in truth only the GUI disappeared, the VLC window, while the program itself remained running in the memory.

I opened the Windows Task Manager and saw the VLC process. Right clicking on it and terminating it, finally closed VLC. After that the global hotkeys of Winamp worked as usual.

Therefore, especially if your global hotkeys used to work, and suddenly today seem to face this problem, recall which programs you run recently in case some of them interfered with Winamp.