Is there a way to control winamp in the windows lock screen?
When i press the play / pause button on my multimedia keyboard it control winamp, but not when the computer is locked.
Normally, the answer would be no. When your session is locked, the lock screen is displayed on a separate desktop, to prevent any possible information leaks or meddling with the running programs.
(The volume controls work because they are managed by Windows itself (probaby Winlogon). You might have noticed that they keep working when Winamp is closed.)
It is possible to run other programs in the secure desktop: