Copying to clipboard is a problem in vista

HI guys,
Im having a code, to copy to a clipboard from any selected area of any application but this dosnt works in vista,even keyboardevent fails

keybd_event(VK_CONTROL, 0, 0, 0); // Ctrl Press
keybd_event((unsigned char)VkKeyScan('C'), 0, 0, 0); // 'C' Press
keybd_event((unsigned char)VkKeyScan('C'), 0, KEYEVENTF_KEYUP,0); // 'C' Release
keybd_event(VK_CONTROL,0 ,KEYEVENTF_KEYUP,0); // Ctrl Release

It works fine in XP,is their any security options to be changed in vista pls letme know.

Thanks in advance.