Hi Zhixue, There is not enough information in your message. It would be useful to know: (1) Could you do what you wanted with an earlier version of Chimera such as 1.6? The procedure should be the same as in earlier versions of Chimera. Here is a general description of how to select: <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/selection.html> (2) Which part could you not do, was it the selecting part or the deleting part? (3) Do you mean selecting with the mouse, or any selecting (such as with the Select menu)? There was one earlier message about trouble selecting with the mouse in Chimera 1.7, <http://plato.cgl.ucsf.edu/pipermail/chimera-users/2013-January/008368.html> ...and we would like more information about that. So if you might be having the same problem (or in general, when you believe there is a bug) instead of emailing here, please use "Help... Report a Bug" in the Chimera menu, and include a description, and your email address if you would like a response. Thanks, Elaine ---------- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Jan 28, 2013, at 7:57 PM, Zhixue Zhu wrote:

Dear Sir/Madam:

I just installed Chimera 1.7. However, I can not select individual atom or a group of atoms and then delete them. Please give some advice and instructions.

Regards

Zhixue