For example, you put your VB executable on a system and attempted to execute. An error message stated...
Component 'mscomctl.ocx' or one of its dependencies not correctly registered: a file is missing or invalid.
You could obtain a copy of mscomctl.ocx and just drop it in the same folder as your executable. However, this is not the correct way of doing things in Microsoft Windows.
Place mscomctl.ocx in c:\windows\system32 then register the component with the following command:
regsvr32 \windows\system32\MSCOMCTL.OCX
Which creates an entry in the windows registry and makes the component available to all Windows applications which may require it under Windows XP.