做个API拦截

是用API作键盘信息的拦截吗？那要应用到键盘钩子，你要我可以把代码发给你(代码是网上摘录的)。但是你要求“用软件”，那就有点问题了，除非你说明要拦截什么按键，否则只有你自己修改代码了。
'.bas模块中
Public m_hDllKbdHook As Long 'public variable holding
'the handle to the hook procedure

Public Const WH_KEYBOARD_LL As Long = 13 'enables monitoring of keyboard
'input events about to be posted
'in a thread input queue

Private Const HC_ACTION As Long = 0 'wParam and lParam parameters
'contain information about a
'keyboard message

Public Const VK_CAPITAL As Long = &H14
Public Const VK_NUMLOCK As Long = &H90
Public Const VK_SCROLL As Long = &H91

Private Const VK_TAB = &H9 'virtual key constants