INSTAGRAM made is a free application for smartphones (or tablets) Android or Apple to instantly share photos with friends. However, understand that INSTAGRAM is unusable with a computer (can not upload photos etc). You can only view the pages of subscribers, no more ... ;-) So try to download to your computer INSTAGRAM does you NOTHING. The application is also totally incompatible with Windows. To share your photos on PC with your friends, so choose rather FLICKR, PICASA, or Kizoa.
INSTAGRAM, is reserved for regulars handling tablets and Android and Apple smartphones. Exclusive Windows users, this app does not concern you.