I really want to switch from Windows 7 Home Premium to Ubuntu, but I need to know if my programs i currently have installed on my laptop will be removed. Thanks
All your programs will be removed, just everything. Of course instead of deleting Windows completly, you can have both, Windows and Ubuntu, then your Windows' data will remain, although notice that Ubuntu and Windows are different Operational Systems (OSs).
Programs that run on Windows are made in its code, so when you get Ubuntu you will need programs for Ubuntu's code, some Windows applications are available for Ubuntu too, although many not, and for that cases there are "equivalents" in Ubuntu.
You should learn more about Ubuntu before installing it in its official webpage. Just a hint for you, in case your work depend on professional and specific features of tools like Autodesk, MS Office, Visual Basic, etc. You almost certainly will be doing a bad movement as you will need time to learn how to do the same work with the different Ubuntu's apps, and there are cases in which you may need very, very specific tools and features that may not be available in Ubuntu.
Last but not least, I am not saying you: "Hey, its bad turning to Ubuntu"; the OS is great, although you need to confirm, before installing it, if you will be able to accomplish your tasks in the new environment. If you just use the PC for web, video, music, reading and common tasks, then I will say to you: Why haven't you tried Ubuntu yet?
Windows will not be affected if you use the wubi installer. Put the Ubuntu live cd into your computer, and run wubi setup in windows. You will then have the computer dual booted, with Ubuntu. if you don't like Ubuntu, sinmply go into add and remove programs and uninstall Ubuntu from Windows.