>Is there a way to block the alt and windows keyboard keys from a VFP application? I want to deactivate alt+tab, alt+ctrl+del and the start button key and reactivate later in some special events at my application.

Luis,

See HOWTO: Block CTRL+ALT+DEL and ALT+TAB in Windows 95 or Windows 98 from the MS Knowledge base. Note that this technique cannot be used under WinNT/2K. Also note the warning in the article.