vb.net program to rename all files in a folder

i have 1500 files in a folder. they have names such as [login to view URL], [login to view URL] etc all the way to 1500. i need them all renamed using this format: [login to view URL] RENAMED TO [login to view URL] [login to view URL] RENAMED TO [login to view URL] [login to view URL] RENAMED TO [login to view URL] [login to view URL] REMAINS THE SAME so what is happening is that the numeric part of the filename is changed from an ordinary number into a four digit number, with leading zeros unless it is already a four digit number. It should be a very simple application, with one button to select target folder and another button to start the process to finish. It should be written in VB.NET 2008 or older and I want the source code.