I recently came across a program called TikZ, for creating graphics. I don't know how to install it! In its website I didn't see any instructions. Could any one help me? I am using Windows 7 Home edition. Thanks
TikZ is not a "program", but a package for LaTeX (and other versions of TeX). If you just want to create graphics and don't know anything about (La)TeX you should make yourself familiar with that (e.g. by reading the article about LaTeX on wikipedia).
If you are using LaTeX, you can use TikZ with
if it is included in your TeX distribution (which is the case for most distributions).