Some installations or settings changes require you to restart your computer. In most cases you don't need to actually reboot it, you only need to restart the explorer.exe process.
Zip files are compressed archives containing documents, images, folders, basically any type of files on your computer. We create them to save space and make them more practical for sending via email or file sharing services.
Windows 7 have a nifty feature which combines the windows of opened applications under the same taskbar button. If you don't like it you can always turn it off.
