I created Getting Started with LaTeX page with the instructions how to install LaTeX on a Windows computer. The installation recommended here will give you a choice of three LaTeX editors: TeXworks, which is a part of MiKTeX, TeXstudio and TeXmaker. You can try each editor and choose one that suits you the best. You can also look for a better one on the web. I use WinEdt, which is a shareware ($40) and available only in the lab BH 215. You can try this editor for free for 30 days.
Here is a simple LaTeX sample document in which I prove an interesting inequality.