Let's see, you are doing VB.net, you are probably running some version of IIS--or I think Microsoft was a personal server that does not include SMTP. You need to first determine what type of webserver you have installed on your machine, and if SMTP is part of it. SMTP stands for Simple Mail Transfer Protocol. If you have IIS installed, then you need to determine if the SMTP service is enabled, and then if it is running. See this link for more: http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/cc7996c9-708c-46d3-9410-83d45e49e8ab.mspx?mfr=true
go to computer, right click and then to Manage. Go to services and applications, then internet information services, click on it to see all of its subparts and go to the smtp email. If it is not in the local services on your machine, that's why you are not able to send email. you will have to go out on the web and determine how to add that service on your machine--you should be able to simply follow some directions to enable it--it is not something you will have to download and install as far as I know. You should search under something like "enabling SMTP under IIS" online to find the directions you need. You might verify how it is configured based on the version of Windows 7 that you have also. These are the core issues for your problem as far as I can tell from reading your posts.