Website Fails To Use (Recognize) The Latest Versions of modified .aspx.vb Files I have ftp uploaded

I just recently uploaded a new website. After making changes (in Visual Studio) to several .aspx.vb files I ftp uploaded them to the site; however the web application continues to utilize the old versions
of these files. I have tried stoppng and starting the web application as well as recycling the application pool (I have also tried deleting just the pages in question then re-ftp'ing but that didn't work either.
The onlysuccess I have had so far is isto delete the entire site and re-ftp all of it back up.

Obviously, I need to be able to just upload changed content and have it take effect. What am I doing wrong here? Thanks in advance to anyone who can help.

Note: my application is in the root directory