First of all Why in the world would u even want to make a keylogger in a .bat If your going to send this to a network A.K.A school im pretty sure there system admin keeps a logs of all events on the system if one appears to yours and the admin sees it and takes a look at the .bat he can easily view the source

Dont make it in VB best advice C# / C/C++ why not vb? You can easily decompile code in VB rather than c# C/c++ If you need help on creating one i wouldnt mind teaching you